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Basic Quality Criteria in Food Control
Lecture 1
• Food Quality
Quality can be defined as combinations of
attributes or characteristics of a product that
have significance in determining the degree of
acceptability of that product to the consumer.
Food Quality
It can also be said as measure of purity,
strength, physicochemical & oregano-leptic
characteristic of food products but the classical
definition of quality is composite of these
characters that differentiate between individual
units of the products & have significance in
determining the degree of acceptability of that
unit by the user
Definition
Quality is a measure of the degree of excellence or
degree of acceptability by the consumer. It can be
defined as “summary of features and characteristics
of a product or service that bear on its ability to
satisfy stated or implied needs”. In simple words the
product should have attributes to “satisfy the
wants/ needs of the consumer or conformance with
the user’s requirements”. It also covers the safety
and value for money. Food quality can be
considered as
a complex characteristic of food that determines
its value or acceptability to consumers. Thus it
may be defined as “the composite of those
characteristics which have significance in
determining the degree of acceptability by the
buyer. These characteristics should also have the
ability to differentiate individual unit of the
product.”
Every food product has characteristics and indices
measurable by sensory, physicalchemical,
or microbiological methods. Some characteristics are
easily perceived; others are unseen. Understanding
these quality characteristics and being familiar with
the appropriate measuring tools are vital to quality
control and the quality assurance of food
products.
Components
The important components of food quality are:
food safety, sensory characteristics and nutritional
value. Safety of food is a basic requirement of food
quality. “Food safety” implies absence or
acceptable and safe levels of
contaminants,adulterants, naturally occurring
toxins or any other substance that may make food
injurious to health on an acute or chronic basis.
Besides safety, quality attributes include: nutritional
value; organoleptic properties such as appearance,
colour, texture, taste; and functional properties.
Components:
The quality attributes are outlined in Table and includes primarily
sensory attributes and hidden attributes. The sensory attributes
include characteristics such as colour and appearance, viscosity
and consistency, smell, taste, touch etc. The hidden characteristics
are those which cannot be evaluated with human senses and yet
are of real importance to human health and welfare. Nutritive
value is one of the hidden characteristics, which is now considered
by the consumers as a quality attribute. Adulterants and toxicants
are the other hidden characteristics. Toxic substances may be of
microbial origin, veterinary drugs residues, pesticide residues or
heavy metals.
Table1. The quality attributes
The quality attributes are outlined in Table and
includes primarily sensory attributes and hidden
attributes
i) Food safety:
In order to understand “food safety” we must first know the
terms safe and hazard. “Safe” means that nothing harmful
happens when we consume a food. A “hazard” is the capacity
of a thing to cause harm. The objective of the food safety is to
protect the food supply from microbial, chemical and physical
hazards or contamination that may occur during all stages of
production and handling-management of animals at farm,
transportation,storage of raw milk, processing, production of
value added products, distribution and storage of end
products. It aims for keeping food wholesome and free from
food borne illness. The important associated definitions and
factors are described for better understanding of the food
safety.
a) Food borne illness:
Food borne illness or food poisoning is caused
by consuming food contaminated with
pathogenic bacteria, toxins, viruses or parasites.
The contamination may or may not alter a food’s
organoleptic properties but cause illness and
disease to human beings after consumption and
usually arises from improper handling,
preparation or storage of food.
Food-borne diseases are classified as food infections or
food intoxications. Food infections involve
microorganisms present in the food at the time of
consumption which then grow in the host and cause
illness and disease.Food intoxications involve toxic
substances produced in foods by microorganisms prior to
consumption and cause disease upon ingestion.The toxin
producing microorganisms need not to grow in the host
to produce a disease or even be present in the food. So
we must acknowledge that intoxication can occur even if
no viable microorganisms are ingested.
(b) Food hazards:
Food becomes hazardous by contamination.
Contamination is the unintended presence of harmful
substances or microorganisms in food. Food hazards can
be defined as a biological, chemical or physical agent in
a food, with the potential to cause an adverse health
effect (Table). Physical hazards are foreign particles, like
glass/wood or metal pieces, stone, bone fragments,
feathers, fibre, hair, etc. Chemical hazards include
substances such as cleaning solutions and sanitizers, non
permitted adulterants, pesticide and heavy metal
residues. Biological hazards come mainly from
microorganisms
Quality ,Ministry of Health is pursuing a broad
and long-term sciencebased strategy to improve
the food safety and to better protect the public
health. Part of this strategy is a farm-to-table
approach to improve the safety of food at each
step in the food production, distribution,
and marketing chain
Table2. Types of Food Hazards
(d) The Food Safety and Standards Act, 2006:
The chapter six of the Act titled as “Special
Responsibilities as to Food Safety” deals with
responsibilities of the food business operator,
liability of manufacturers, packers, wholesalers,
distributors and sellers and recall procedures
(e) Safety concerns: We know that the goal of food
safety is to reduce the size of risks to the lowest
reasonable level without severe disruption of the
food supply. For this we should first identify hazards
related to foods or food components and then
estimate the size of the risk that the hazard will
cause. It is important to note that all foods have
some degree of risk and that no food is absolutely
“safe.” The important consideration becomes “the
size of the risk and how the size of the risk can be
reduced” without eliminating the food source.
Specific food safety concerns differ
markedly and include
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Additives, colours and flavours.
Antibiotics and other food additives.
Fertilizers and other growing aids.
Irradiation.
Microbiological contamination.
Naturally occurring food toxicants.
Nutrition.
Pesticides.
Pollutants.
Processing, packaging and labelling.
Tampering.
(f) Adhering to Safety Standards:
The advantages associated with adhering to food safety
standards are:
• Ensures safety of food products.
• Greater health protection.
• Increased international acceptance of food products.
• Helps to meet applicable food safety related statuary
& regulatory requirements.
• Demonstrate conformance to international standards
and applicable regulatory requirements.
• Reduces risk of product/service liability claims.
(g) Recent Concerns of Food Safety: Prions,
genetically modified foods, the incidence of
bovine spongiform encephalopathy (BSE), and
dioxincontaminated foods are some of the new
food safety concerns.
Prions are one of the new sources of food borne diseases. A prion is
the short form of proteinaceous infectious particle. Dr. Stanely
Prusiner coined the word “prion” as a name for the infectious agent,
by combining the first two syllables of the words “proteinaceous” and
“infectious.” While the infectious agent was named a prion, the
specific protein that the prion was made of was named PrP, an
abbreviation for “protease-resistant protein”.The normal form of the
protein is called PrPC, while the infectious form is called PrPSc, which
stands for prion protein of scrapie. Prions are generally quite resistant
to denaturation by protease, heat, radiation, and formalin treatments,
although potency or infectivity can be reduced. Prions enter cells and
apparently believed to infect and propagate by refolding abnormally
into a structure which is able to convert normal
The diseases associated by prisons are:
Creutzfeldt-Jakob Disease (CJD), Bovine
spongiform encephalopathy (BSE- commonly
known as “mad cow disease”), fatal familial
insomnia and kuru (translated as “to tremble
with fear”).
Dioxin–Contaminated Foods: Dioxin is the popular name
for the family of halogenated organic compounds, the
most common consisting of polychlorinated
dibenzofurans (PCDFs) and polychlorinated dibenzopdioxins (PCDDs). PCDD/PCDFs are industrial pollutants
that persist in the environment. They have been shown to
bio accumulate in humans and wildlife due to their
lipophilic (fat loving) properties. Dioxins are a carcinogen
in higher amounts, and cause developmental and
reproductive problems. They are absorbed primarily
through dietary intake of fat, as this is where they
accumulate in animals, including humans
Genetically Modified (GM) Foods: The GM foods
are produced from genetically modified organisms
(GMO). A GMO means: an organism that has been
modified (manipulation of DNA) by gene
technology. Genetically modified (GM) crops and
food are being grown and consumed by the public.
The advantages associated are: increased yields
from agriculture,more powerful control of pests
and weeds, reduced use of some agrochemicals and
enhancement of nutritional value or other
characteristics of crops, etc.
There are many things which people hold up as
possible dangers of genetic modification: risk of
transferring crop traits to wild species, negative
impacts on wildlife from more powerful control
of pests and weeds, increased use of some
agrochemicals, increased corporate control of
seed supply and; limited studies on food safety
concerns on human health in form of toxins/
allergenic reactions/ reduction in good micro
flora of duct, etc.
ii) Nutritional Value:
Nutritional value of the product has grown in
importance as consumers have become better
informed about foods. The consumers demand for
nutritional labelling in addition to food safety.
Nutritional changes occur in foods during handling,
processing and storage due to microbiological,
enzymatic and chemical reactions. One of the
principal responsibilities of the dairy technologists
is to preserve nutrients through all phases of food
acquisition,processing, preparation and storage.
ii) Nutritional Value:
As a food processor, we should have good knowledge
of the stability of nutrients under different conditions.
Vitamin A is highly sensitive (i.e., unstable) to acid, air,
light, and heat; on the other hand,vitamin C is stable in
acid but is sensitive to alkalinity, air, light, and heat.
Because of the instability of nutrients under various
conditions and their water solubility, cooking losses of
some essential nutrients may be greater than 75%. In
modern food processing operations, however, losses
seldom exceed 25%. The food should not contain any
toxic/ anti- nutritional substances.
iii) Sensory Characteristics:
The sensory characteristics of foods and
materials are based on perception of human
senses i.e. senses of sight, smell, taste, touch
and hearing.
QUALITY EVALUATION
• Three methods; 1 Subjective method 2. Objective
method 3.microscopic method
• 1. Subjective Method; Evaluating quality are
based on opinion of the investigators. it includes
sense organs. It is usually a physiological reaction
which is a result of past training, experience of
the individual influence of personal preference
& power of perception. It is also referred as
subjective or sensory method e.g. flavor, color,
touch, odour and taste.
• 2. Objective method; objective methods of quality are based on
observations from which the human perception is excluded. They
are based on scientific tests.
• Physical methods of Measurement; This is perhaps the quickest
method s are generally. They are concerned with such attributes of
product quality as size, texture, color, consistency imperfections or
they may be concerned with process variables like headspace, fill,
drained weight, or vacuum
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• Chemical methods of measurement. Standard analysis methods
are generally used for quantitative chemical evaluation in most
cases , but these chemical analysis are often too long & tedious as
a result industries have developed method termed as quick test
for such as those for ; enzymes, moisture, fiber, pH or acidity
• 3. Microscopic method
• They have excellent application in a quality control
programme because they help in determination of
microbial count, spoilage protection in fresh and
processed products and can differentiate between cell
types and organisms. These methods can be divided
into two categories
• Adulteration & contamination
Examination will indicate the presence of molds, insects,
excreta or foreign material. Each test is specific.
Differentiation between cell type , tissue type,& m/o of
various stored foods
Lecture 2
Food Quality (Cont)
Food Quality
Quality can be defined as combinations of
attributes or characteristics of a product that
have significance in determining the degree of
acceptability of that product to the consumer
Factors contributing towards quality of food
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Nutritional value
Appearance
Color
Taste
Odor
Adulterants
Contaminants
(Physical,
Microbiological
Chemical
&
• Nutrient means any substance normally
consumed as a constituent of food:
• Which provides energy; or
• Which is needed for growth and development
and maintenance of healthy life; or
• A deficit of which will cause characteristic biochemical or physiological changes to occur
Proximate analysis of foods refers to determining the major
components of foods
• Moisture (db or wb)
• Ash (total minerals)
- AIA, Sulphated ash, Water soluble Ash, Water Insoluble Ash
• Fats/lipids
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Saturated fats
MUFA
PUFA
PUFA
• Protein
• Carbohydrates
- Reducing sugar/ Non reducing sugar
• Crude Fibre
• Energy (Calories)
Benefits of Nutritional analysis- Food quality
parameters
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Better quality check
Increasing Product consistency
Easy Processing & Formulations
Better Preservation
Easing marketing and distribution tasks
Increases yearly availability of many foods
Enables transportation of foods across long distances
reduces the incidence of food borne disease.
Improve the quality of life for people with allergies, diabetics,
and other people who cannot consume some common food
elements
• Enables better food fortification
Moisture Analysis
• Moisture is an important factor in
food quality, preservation, and
resistance to deterioration
Moisture is a quality factor:
-Dehydrated vegetables and fruits
-Dried milks
-Powdered eggs
-Dehydrated potatoes
-Spices and herbs
-Jams and jellies to prevent sugar
crystallization
Sugar syrups
-Prepared cereals – conventional and instant mixes
-Concentrated milks
-Liquid cane sugar (67% solids) and liquid
corn sweetener (80% solids)
• Dehydrated products (these are difficult to package if too high in
moisture)
• Concentrated fruit juices
• Moisture (or solids) content is often specified in compositional
standards (i.e., Standards of Identity)
• The percentage of added water in processed foods is commonly
specified.
Total Ash/ Minerals
Ash refers to the inorganic residue remaining after either
ignition or complete oxidation of organic matter in a foodstuff.
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Ash content represents the total mineral content in foods.
The ash content of most fresh foods rarely is greater than 5%.
Pure oils and fats generally contain little or no ash
Fats, oils, and shortenings : 0.0 to 4.1% ash
Dairy products : 0.5 to 5.1%
Fruits- Fruit juice: 0.2–0.6%
Dried fruits : 2.4–3.5%
Flours and meals: 0.3 to 1.4%
Pure starch contains : 0.3%
Nuts and nut products : 0.8–3.4%
Fat Analysis
Fat analysis is important for:
• Quantitative and qualitative analysis of lipids in foods is
important for accurate nutritional labeling
• Determination of whether the food meets the standard of
identity
• To ensure that the product meets manufacturing
specifications
• Lipids in food are subjected to many chemical reactions
during processing and storage
• To ensure product flow and consistency
Fatty acid composition of different oils
Edible oils
Olive Oil
Canola Oil
Mustard Oil
Lard
Sesame Oil
Rice bran Oil
Palm Oil
Ghee / Butterfat
Corn Oil
Soyabean Oil
Grapeseed Oil
Sunflower Oil
Cottonseed Oil
Safflower Oil
Coconut Oil
Saturated Fat
MonoUnsaturated Fat
10
07
11
43
14
22
48
68
13
15
11
12
27
10
89
82
61
56
47
42
42
38
28
27
23
20
19
19
14
7
Poly-Unsaturated Fat
Omega-3 Fatty Omega- 6 Fatty
Acid
Acid
*
11
15
1
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*
*
1
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8
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*
*
*
*
8
21
18
9
44
36
14
3
60
54
69
69
54
76
4
Protein
• Protein analysis is important for:
1. Nutrition labeling
2. Pricing: The cost of certain commodities is based on the
protein content as measured by nitrogen content (e.g., cereal
grains; milk for making certain dairy products, e.g., cheese).
3. Functional property investigation:
- gliadin and glutenins in wheat flour for breadmaking,
- Casein in milk for coagulation into cheese products
- egg albumen for foaming
4. Biological activity determination:
- The proteolytic enzymes
- Pectinases in the ripening of fruits
2. Factors Determining Food Quality
2.1. Sensory Properties
2.1.1. Appearance and Color
2.1.2. Texture
2.1.3. Taste and Flavor
2.2. Physical Properties
2.3. Chemical Composition
2.3.1. Moisture Content
2.3.2. Fat Content
2.3.3. Food Protein
2.3.4. Carbohydrates
2.3.5. Vitamins
2.3.6. Minerals
2.4. Food Additives
2.5. Microbiological Characteristics
2.6. Other Natural or Synthetic Components Influencing Quality and Safety
2.7. Packaging and Labeling
Factors Determining Food Quality
2.1. Sensory Properties
The measurement of sensory properties and
determination of the importance of these
properties to consumer product acceptance
represent major accomplishments in sensoryn
evaluation. These achievements have been possible
as a direct result of advances insensory evaluation,
in the application of contemporary knowledge
about the measurement of human behavior, and in
a more systematic and professional approach
totesting.
2.1. Sensory Properties
Man accepts food on the basis of certain
characteristics that he defines and perceiveswith his
senses. These attributes are described in terms of
sensations and are sometimes referred to as
qualitative or sensory qualities. They include
perceptions of appearance factors such as color,
size, shape, and physical aspects; kinesthetic factors
such as texture, viscosity, consistency, finger feel,
and mouth feel; and flavor factors or sensations
combining odor and taste.
2.2.Appearance and Colour
Color and other aspects of apperaance influence food
appreciation and quality, especially by the consumer. Man
has subjective standards for the acceptable range and
preferred optima for these qualities for almost every
food.The importance of the color of agricultural commodities
and processed foods cannot be overstressed. An important
problem is discoloration or the fading of the colors of various
raw and processed fruits and vegetables. In some cases,
color changes areaccompanied by undesirable changes in
texture, taste, or odor. Overaged cheese, beer,meat, and fish
all develop off-color, which the consumer recognizes as
being associatedwith poor flavor quality.
Five functions that should be considered in
understanding human reactions to color in
foods are
• Perception. Food selection or judgment of food quality would be
extremely difficultif color discrimination were removed, even though
size, texture, shape, and othercues were left intact.
• Motivation. Food color and the color of the environment in which the
food is seencan significantly increase or decrease our desire or appetite
for it.
• Emotion. Liking or disliking a food is conditioned by its color; attractive
foods aresought out as pleasure-giving, while unattractive foods are
avoided.
• Learning. By the process of experience, we learn what color to expect
and consider“natural,” and we predict rather precisely what properties a
food or beverage willhave from our memory of similar materials.
• Thinking. Our reaction to unusual properties or to new foods can be
changed if theyare explained to us.
2.3. Texture
Texture can be described as the properties of a
foodstuff apprehended both by the eyes and by
the skin and muscle senses in the month,
embracing roughness, smoothness, graininess,
and so forth.
Texture
The texture or mouth feel of liquid foods,
especially those that behave as Newtonian
fluids, is closely related to their viscosity. When
the degree of gum solution sliminess was
evaluated by a trained panel, mouth feel ratings
were correlated with viscosity.
The texture of fruits and vegetables has been
assessed with instruments that measure
compression, resistance to penetration, or force
required to shear.
The Magness pressure tester, wherein a steel
plunger of a specified diameter penetrates the flesh
of a fruit, is used widely for determination of the
maturity of deciduous fruits. Variouspenetrometers
have been developed for objective evaluation of the
texture of cooked,canned, and frozen foods.
The most important components of
food texture are
flavor
When food is consumed ,the interaction of taste,
odor, and textural feeling provides an overall
sensation that is best defined by the English word
“flavor.” German and some other languages do not
have an adequate expression for such a broad and
comprehensive term. Flavor results from
compounds that are divided into two broadclasses:
Those responsible for taste and those responsible
for odors, the latter often designated as aroma
which provides both sensations.
• Odor, the olfactory perception caused by volatile
substances released from a product in the mouth
via the posterior napes
• Taste, gustatory perceptions (salty, sweet, sour,
bitter) caused by soluble substances in the mouth
• Chemical feeling factors that stimulate nerve ends
in the soft membranes of the buccal and nasal
cavities (astringency, spice heat/cooling, bite,
metallic flavor,umami taste).
flavor
Flavor is the most important sensory property of
many food products. Flavor, as an attribute of
foods, beverages, and seasonings, is defined as the
sum of perceptions resulting from stimulation of
the sense ends that are grouped together at the
entrance of the alimentary and respiratory tracts.
For the purpose of practical sensory analysis, the
term for the impressions perceived via the chemical
senses from a product in the mouthis restricted.
Defined in this manner, flavor includes
flavor
The threshold concentrations (values) for aroma
compounds are dependent on their vapor
pressure, which is affected by both temperature
and medium. The values are also influenced by
the assay procedure and/or performance of the
sensory panel. The frequent discrepancies in
threshold values in the literature are basically
due to suchdifferences.
Particularly important aroma constituents are
those compounds that bear the characteristic
aroma of the food, the so-called “character
impact compound.” With regard to the
occurrence of such key compounds, food can be
divided into four groups
2.3. Chemical Composition
The nature and amount of substances in a given
food product determine the nutritive value and
other properties. As the development and
enforcement of standards of identity and purity, the
control of food safety is based on the determination
of chemical composition, including chemical
contaminants. Analysis of the molecular
composition of food substances is known as
proximate analysis. It is used to study the protein,
fat, carbohydrate, ash, and water content of foods (
2.3.1. Moisture Content
Water (moisture) is the predominant constituent in many
food products (Table 4). As amedium, water supports
chemical reactions, and it is a direct reactant in hydrolytic
processes. Therefore, removal of water from food, or
binding it by increasing theconcentration of common salt
or sugar retards many reactions and inhibits the growth
ofmicroorganisms, thus improving the shelf life of a
number of foods. Through physicalinteraction with
proteins, polysaccharides, lipids, and salts, water
contributes significantly to the texture of food
Food products with aw values between 0.6 and
0.9 are known as “intermediate moisture
foods.” These food products must be protected
extensively against microbial spoilage.
One of the options to decreasing water activity,
and thus improving the shelf life of
food, is to use additives with high water-binding
capacities (
2.3.2. Fat Content
The majority of lipids are derivatives of fatty
acids. In these so-called acyl lipids the
fatty acids are present as esters and in some
minor lipid groups in amide form. The acyl
residue influences strongly the hydrophobicity
and the reactivity of the acyl lipids.
The nutritive, physiological importance of lipids
is based on their role as fuel molecules
(39 kJ/g triglycerides), and as a source of
essential fatty acids and vitamins. Apart from
their roles, some other lipid properties are
indispensable in food handling or processing.
These include the pleasant creamy or oily
mouthful, and the ability to solubilize many
taste and aroma constituents of food
2.3. Chemical Composition
2.3.1. Moisture Content
2.3.2. Fat Content
2.3.3. Food Protein
2.3.4. Carbohydrates
2.3.5. Vitamins
2.3.6. Minerals
2.4. Food Additives
2.5. Microbiological Characteristics
2.6. Other Natural or Synthetic Components Influencing
Quality and Safety
2.7. Packaging and Labeling
3. Overall Evaluation of Food Quality
Why use Additives ?
 Food produced on the large scale that is needed to
supply supermarkets and other food shops has to be
transported and stored before it is consumed .
 It has to stay in top condition over a much longer
period of time than home cooked food.
 Additives are used so that these foods still have a
consistently high quality.
What are food additives?
• They are chemicals ,or ingredients which are added
to food products for maintaining their stability.
• Additives are artificial or natural chemicals , added
to food , for microbial and chemical stability of foods
or delay or even stop food rancidity.
The Codex Alimentarious Commission has defined
“Food Additive” as under: Food Additive means any substance not normally
consumed as a food by itself and not normally used as a
typical ingredient of the food ,whether or not it has nutritive
value, the intentional addition of which to food for a
technological purpose in the manufacture, processing,
preparation, treatment , packing, or holding of such food
results, or may be reasonably expected to result in it or its
bye products becoming a component or otherwise
affecting the characteristics of such foods.
The term does not include contaminants or substances
added to food for maintaining or improving its nutritive value.
Functions of food additives:
• Improve the taste or appearance of a processed food
Eg: beeswax –glazing agent is used to coat apples
• Improve the keeping quality or stability of a food
Eg: sorbitol –added to mixed dried fruit to maintain
moisture level and softness of the fruit
Functions of food additives:
• Improve shelf life or storage time
Eg: sulphurdioxide added to sausage meat to avoid
microbial growth
• Ensure nutritional value
• Maintain uniform quality and to enhance quality
parameters like flavour,colour etc., in large scale
production
Types of food additives:
Direct or intentional food additives which are
added deliberately to improve its sensory quality,
stability, ease in processing and retention of quality
during handling and retailing .
Indirect or unintentional food additives which get
included into foods incidentally during handling,
processing and packaging.
Classes of food additives
 Preservatives.
 Food colours.
 Food flavors and flavor enhancers
 High intensity / lowcalorie sweeteners.
 Antioxidants.
Emulsifiers.
Acidulants
Anti-caking agents
E-Codes
• E-codes are codes sometimes found on food labels
in the European Union (Great Britain, France,
Germany, Spain, Italy, Portugal etc.)
• The codes indicates an ingredient which is some
type of food additives
• The “E” indicates that is a “European Union
Approved” food additive
• Other countries have different food labeling laws
E-Codes number
E-100
E-200
E-300
E-400
E-500
E-600
Groups of Food Ingredients
Coloring agents
Preservatives
Anti-oxidants
Thickeners, Stabilizers,
Gelling agents, Emulsifiers
Agents for physical
characteristics
Flavor enhancers
What are the effects of food additives?
Immediate effects:
Headache
Change in energy level
Alterations in mental concentration, behavoiur , or
immune response
Long term effects:
Increase risk of cancer ,cardiovascular disease and
other degenerative conditions
Preservatives:
• They prevent spoilage of food due to fungi , bacteria
and other microorganisms
• Commonly used in
Low fat spreads
Cheeses, margarine, mayonnaise
Bakery products
Dried fruit preparations
Eg: sodium benzoate , sodium nitrite, benzoic acid
,BHA(butylated hydroxy anisole ) /BHT(butylated
hydroxy toluene)
Sodium benzoate- carbonated drinks ,pickles ,
sauces
Side effects:
aggravates asthma and suspected to be a
neurotoxin and carcinogen , may cause fetal
abnormalities .
Worsens hyperactivity
Food Safey –Natural Toxins
Hazards in Food
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Physical:glass, stone, metal, wood, etc
Chemical:
-natural toxins
-residues
-metals
-toxins formed during food processing
Microbiological:pathogenic microorganisms
(bacteria, viruses, parasites, etc)
• Naturally Occuring Toxins in Food
• Man Made Toxins
Natural Toxins
•They are naturally present in plants & animals.
•The long term ingestion of natural toxins in
commonly eaten foods 􀃆the risks to human health?
•Usually, natural toxins are not acutely toxic, except
in a few cases in animals.
•Most of the natural toxins, particularly those
occurring in plant-derived foods, induce adverse
effects only after chronic ingestion or by allergic
reactions.
An Overview of Natural Toxins in Food
What are Natural Toxins in Food?
As opposed to man-made chemicals such as
pesticides, veterinary drugs or environmental
pollutants that get into our food supply, toxins
can be present due to their natural occurrence
in food. Natural toxins found inherently in foods
of plant and animal origins can be harmful when
consumed in sufficient quantities.
Risks of toxins in food
General toxicity (instant death or illness)
•Carcinogenic
•Mutagenic
•Teratogenic
•Endocrine disrupters (hormones)
•Microbial pathogens
Natural Toxins in Foods
•Endogenous toxins of plant originToxic phenolic substances:
flavonoids, tannins, coumarin, safrole, and myristicin
Cyanogenic glycosides
Glucosinolates
Acetylcholinesterase inhibitors
Biogenic amines
Central stimulants
•Natural contaminants Mixing of edible plants with toxic plants
Contamination resulting from intake of toxic substances by animals
Microbial toxins
Natural Toxins Present in Food of
Plant Origin
Of over 300 000 different plant species in the world,
at least 2 000 species are considered to be
poisonous. Cases of poisoning are often reported
when wild species of mushrooms, berries or other
plants are ingested. Globally, only hundreds of plant
species are commonly eaten, yet many of them can
become toxic to the body if they are taken in excess
or if they are not properly treated before
consumption. Depending on the species, the edible
parts of plants vary, which may include foliage,
buds, stems, roots, fruits and tubers, and so are
their poisonous parts.
Natural Toxins Present in Food of
Plant Origin
Plants from the same genera may exhibit similar or vastly
different toxicities. The amount and the distribution of the
toxins present in a plant vary according to the species as well
as the geographical conditions where it is grown.
In general, plant organs that are important for survival and
reproduction, such as flowers and seeds, will concentrate
defense compounds. These compounds may be more rapidly
synthesized or stored at certain stages of critical growth, i.e. in
buds, young tissue or seedlings as in the case of potato
sprouts.
Common examples of natural toxins in food plants include
glycoalkaloids in potatoes, cyanide-generating compounds in
bitter apricot seeds and bamboo shoots, enzyme inhibitors
and lectins in soya beans, green beans and other legumes
Sprouted potatoes
Solanine. Another natural toxin, solanine, is
found in some potatoes. Your mother told you
not to eat potatoes with a green tinge and to
throw away sprouted potatoes, and she was
right
Mushroom Toxins
•Caused by the high content of amatoxins in
mushrooms.
•Mushrooms identified as containing amatoxin
toxins are the species Amanita bisporigera, A.
temifolia, A. ocreata, A. suballiacea, Galerina
autumnalis, and Lipiota brunneolilacea
There are four categories of mushroom toxins:
1.Neurotoxins
Cause neurological symptoms such as profuse
sweating, hallucinations, depression, spastic colon,
excitement, convulsions, and coma.
Protoplasmic poisons
Cause generalized destruction of cells, which is
followed by organ failure.
3.Gastrointestinal irritants
Produce rapid, transient nausea, abdominal cramping,
vomiting, and diarrhea.
Disulfram-like toxins
4.Disulfram-like toxins are usually nontoxic and produce
no symptoms. However, if alcohol is consumed within 72
hours after eating them, they may produce vomiting,
nausea, headache, flushing, and cardiovascular
disturbances.
*The first symptoms of mushroom poisoning occur within 6–
24 hours after ingestion of the mushrooms (phase one).
*Phase two, also called the gastrointestinal phase, involves
severe vomiting and abdominal cramps, nausea, and watery
diarrhea.
*Phase three lasts about 12–24 hours and is characterized by
improved clinical symptoms; however, it is also the beginning
of liver necrosis.
*Phase four (the last phase), results in hepatic failure,
encephalopathy, internal bleeding, and, often, acute renal
failure. Internal bleeding is usually observed and may cause
complications and death.
•Patients usually die within 5–20 days after ingestion of the
mushrooms
Natural toxins in aquatic organisms
poisoning symptoms include tingling and burning in
face, lips, tongue, and ultimately the whole body,
and parathesia followed by numbness, general
motor incoordination, confusion, and headache.
Microbial Toxin: Mycotoxin
Mycotoxin contamination of food and feed highly depends on
the environmental conditions that lead to mold growth and
toxin production.
•The detectable presence of live molds in food, therefore, does
not automatically indicate that mycotoxins have been formed.
•On the other hand, the absence of viable molds in foods does
not necessarily mean there are no mycotoxins. The latter could
have been formed at an earlier stage prior to food processing.
•Because of their chemical stability, several mycotoxins persist
during food processing, while the molds are killed.
DEFINITION-Mycotoxin
 Myco: fungus.
 Toxin: naturally-produced poison.
 Mycotoxins are secondary metabolites
of fungi that are recognized as toxic to other life forms.
 Can be heat stable, not destroyed by canning or other
processes.
Types of mycotoxins







Aflatoxins
Fumonisin
Ochratoxins
Patulin
Citrinin
Trichothecenes
Zearalenone
Aflatoxin
Aflatoxin is the name for a group of toxins (poisonous
chemical compounds) that are produced by two fungi
called Aspergillus flavus and Aspergillus parasiticus.
Aflatoxins
• Aflatoxins are the most important mycotoxins, which is
produced by certain species of Aspergillus (A. flavus
and A. parasiticus), which develop at high
temperatures and humidity levels.
• •Aflatoxins are carcinogenic substances and may be
present in a large number of foods. This toxin can
cause cancer, cirrhosis of the liver.
• •For substances of this type there is no threshold
below which no harmful effect is observed.
• The aflatoxins B1, B2 fluoresce blue and G1, G2
fluoresce green when viewed under a
microscope.
• •A major metabolic product of aflatoxin B1 is
aflatoxin M (usually excreted in the milk of dairy
cattle that have consumed aflatoxincontaminated feed).
• •LD50 ranges from 0.5 to 10 mg/kg body weight
(any species of animals)
• The most common commodities contaminated
are tree nuts, peanuts, and corn and cottonseed
oil.
• The major aflatoxins of concern are B1, B2, G1,
and G2 􀃆usually found together in various
proportions. Aflatoxin B is usually predominant,
and it is the most toxic and carcinogenic.
Ochratoxin
 Aspergillus ochraceus and several other species
including Penicillium produce seven structurally
related secondary metabolites called ochratoxin.
 Ochratoxin is found in a large variety of foods
including wheat, corn, soybeans, barley, coffee beans,
meats and cheese. Barley is thought to be the
predominant source.
Fumonsins
Fumosins are produced by Fusarium
verticillioides, F. proliferatum, and F. nygamai.
Patulin
Patulin is produced by Penicillium clariform, P.
expansum, P. patulum.
Mycotoxins can cause







Death.
Respiratory problems.
Reproductive problems.
Liver, kidney or other organ damage.
Cancer.
Bleeding.
Birth defects.
Mycotoxin Treatment
Mycotoxin poisoning is known as mycotoxicosis. There
is no cure for mycotoxicosis. Antibiotics and drugs have
little effect. The best treatment is to stop the exposure to
mycotoxins.
Natural Toxins Present in Food of
Animal Origin
Natural toxin of animal origin may be a product of metabolism or a chemical
that is passed along the food chain. While poisoning after eating terrestrial
animals is relatively uncommon, poisoning due to marine toxins occurs in
many parts of the world. Marine toxins produced by toxic microalgae are
accumulated in shellfish, crustacean and finfish following their consumption.
Tetrodotoxin, a potent marine neurotoxin, is thought to be produced by
certain bacteria. It is found in over 90 species of puffer fish and may cause
lethality after ingested even a small amount. Seafood poisoning commonly
reported in coral reef fish is due to the presence of ciguatoxin that may be
found in more than 300 species of fish. Histamine produced by bacterial
spoilage of scombroid fish causes another kind of seafood poisoning.
There are approximately 1 200 species of poisonous and venomous animals in
the world. While most of them are not used as food, care must be taken to
avoid the poisonous glands or tissue containing the toxins when these
animals are used as food. Glands of some animals that are not considered
poisonous or venomous when ingested can also cause food poisoning such as
gall-bladder of grass carp which contains the cyprinol related chemicals.
Toxic Effects and Food Poisoning
Natural toxins in food can cause both acute and chronic
health effects with a range of clinical symptoms.
Acute symptoms range from mild gastrointestinal upset,
neurological symptoms, respiratory paralysis to fatality.
This is more likely among the susceptible groups of the
population such as children and the elderly. Within hours
if not shorter, acute symptoms are seen following
ingestion of various marine toxins in shellfish and other
seafood. Acute poisoning is also seen in the consumption
of wild mushrooms or inadequately treated plants such
as ginkgo seeds and bitter apricot seeds.
Toxic Effects and Food Poisoning
Chronic toxicity is seen more often in poisoning
caused by plants toxins such as many alkaloids.
Pyrrolizidine alkaloids that are present in weeds
in crops and in certain plants may cause toxicity
to the liver over prolonged consumption. The
amount of food that would cause toxic effects
depends on the toxin level present as well as
individual susceptibility.
Risk Reduction Measures
In some cases, appropriate methods of food processing and thorough
cooking can be employed to destroy or reduce the level of toxin. In
other cases where the toxin cannot be reduced or removed, intake
should be limited. Thorough cooking destroys enzyme inhibitors and
lectins of beans. Soaking in water, and boiling also remove some
cyanide-generating compounds in the foods concerned. Removal of
gonads, skin, and parts of certain fish eliminates toxins concentrated in
these tissues. In general, whether a substance poses harm depends on
its concentration, amount of intake and the health status of individual
since the body can detoxify low levels of many potentially dangerous
substances. As a rule of thumb, the public should follow the
conventional ways of food processing that are known to be safe, and
maintain a balanced and varied diet so that exposures to certain types
of natural toxins can be kept to a safe level.
Hydrazines. Mushrooms, when eaten raw, are a
source of potentially cancer-causing hydrazines.
Because they're inactivated when cooked, this is
a case where cooked is better than raw.
• Psoralens. Produced in moldy celery, this
relatively mild natural toxin can give you a skin
rash when you're in the sun -- a reaction
called photosensitivity
Residue Problems in Food
Lecture 4
• FOOD SAFETY :A suitable edible product which when consumed
orally either by a human or an animal does not cause any
health risks (to consumer
• RESIDUES:These substances having a pharmacological
actions of their metabolites and of other substances
transmitted to animal products and which are likely to be
harmful to human health.
RESIDUES
Pesticide residues
Heavy metal residues
Antibotic residues
Pest:
“ includes vectors of human or animal disease,
unwanted species of plants or animals
causing harm during or otherwise
interfering with the production, processing,
storage, transport or marketing of food,
agricultural commodities, wood and wood
products or animal feedstuffs”.
Introduction
 When crops are treated with pesticides very small
amounts may remain in or on the crop after
harvesting or storage.
 In order to determine any pesticide residues present
in foodstuffs analytical methods capable of
accurately measuring extremely small amounts of
pesticides are required.
 Gas chromatography is the most used equipment in
pesticide analysis others include High performance
liquid chromatography (HPLC) .
116
A pesticide is any substance or mixture of
substances intended for preventing, destroying,
repelling, or mitigating any pest.
Pests include insects, plant pathogens, weeds,
molluscs, birds, mammals, fish, nematodes
(roundworms), microbes and people that destroy
property, spread or a vector for disease or cause a
nuisance
PESTICIDES
 A pesticide is a substance or mixture
of substance intended for preventing,
destroying, repelling or lessening
the damage caused by the pest.
 A pesticide can be a insect, plant
pathogen, weed, bacteria, bird etc. That compete with the
human for food, destroy property, spread disease.
 A pesticide can be a chemical, biological agent,
antimicrobial, disinfectant etc.
 Many chemical pesticides are poisonous to
human and animals.
Classification of pesticides
1. Herbicide-These are the chemicals used to kill
weeds (i.e., unwanted plants) e.g. Borax,
Nitrofen.
2. Insecticide-These are used to kill insect. E.g.
DDT, BHC.
3. Rodenticide-These are used to kill rodents.
e.g. Warfarin, Zinc phosphide.
4. Nematicide-These are used to kill namatodes
e.g. DBCP, Phorate
5. Molluscicide-These ar used to kill molluscs
e.g Sodium pentachloridephenate.
6.Fungicides-These are used to kill fungus e.g.
Bordeaux mixture
7.Algaecides-These are used to kill algae e.g.
Copper sulphate, Endothal
8.Bactericide-These are used to kill bacteria e.g.
Dichlorophen,Oxolinic acid
9.Piscicides-These are used to kill fishes e.g.
Trifloro methyl nitrophenol(TFM)
Chemical or Synthetic Pesticides
Organochlorenes-These are non-biodegradable and
persist in soil for long time e.g., DDT, BHC, Endosulfan,
Aldrin.
Organophosphate-These are esters of alcohols with
phosphoric acid or with some other acids. These are very
toxic acetyl-cholinesterase inhibitors as a result of which the
breakdown of acetyl choline stops.The accumulation of
acetyl choline resulting in convulsion paralysis and death
e.g.,Malathion.
Carbamates-They are derived from carbamic acid. Mode of
action of carbamates is almost similar to organo- phosphates
e.g.,Carbaryl, Dimetilan.
Working of Pesticides
Pesticides work in the following ways
By blocking the cellular processes of the target organisms
in a purely mechanical way e.g., Spray oils, petroleum oils.
 By destroying or altering the pest’s metabolism e.g.,
Rotenone and cyanide which disrupt respiratory function in
pests.
 By disrupting enzyme processes or denature proteins e.g.
Inorganic Copper compounds
 By simulating or interfering with
hormones e.g., Phenoxy herbicides.
 By disrupting photosynthesis and preventing the weed
plant from producing or storing energy e.g., Triazine.
Benefits of pesticides
• They are used in public health programmes to
control vector born diseases
• They are used to protect the stored food grains.
• They protect the standing crop in the field. They do
not increase the crop yield like fertilizer but by
protecting the crop from pests.
• They can be used to control household pests.
Hazards of pesticides
1. The pesticide industries cause pollution of soil, water and
air.The pesticidal residue washed along with rain water, is
added to the nearby water resources making it unfit for
drinking.
2. They enter the food chain and cause problem of
bioaccumulation or biomagnification.
3. They are not target specific hence also kills non-pest insects.
It adversely affect the mechanism of entomophily.
4.Continuous and indiscriminate use of pesticides may develop
resistance in insect pest like superpest and superbugs.
Pesticides are often referred to according to the:
1) Type of pest they control
2) Derived from a common source or production
method
- chemical pesticides
- biopesticides
- antimicrobials
- pest control devices
Chemical pesticides:
• Organophosphate Pesticides - These pesticides affect the nervous
system by disrupting the enzyme that regulates acetylcholine, a
neurotransmitter. Most organophosphates are insecticides. However,
they usually are not persistent in the environment. (e.g. parathion,
malathion, and methyl parathion)
• Carbamate Pesticides affect the nervous system by disupting an
enzyme that regulates acetylcholine, a neurotransmitter. The enzyme
effects are usually reversible. There are several subgroups within the
carbamates. (e.g. Bendiocarb, Carbaryl, Methomyl, and Propoxur)
• Organochlorine Insecticides were commonly used in the past, but
many have been removed from the market due to their health and
environmental effects and their persistence (e.g. DDT and chlordane).
• Pyrethroid Pesticides were developed as a synthetic version of the
naturally occurring pesticide pyrethrin, which is found in
chrysanthemums. They have been modified to increase their stability
in the environment. Some synthetic pyrethroids are toxic to the
nervous system. (e.g. permethrin, resmethrin, and sumithrin )
• Biopesticides:
– Pesticides derived from such natural materials as
animals, plants, bacteria, and certain minerals.
1. Microbial pesticides consist of a microorganism (e.g. a
bacterium, fungus, virus or protozoan) as the active
ingredient. For example, there are fungi that control certain
weeds, and kill specific insects.
2. Plant-Incorporated-Protectants (PIPs) are pesticidal
substances that plants produce from genetic material that
has been added to the plant.
3. Biochemical pesticides are naturally occurring substances
that control pests by non-toxic mechanisms (e.g. insect sex
pheromones that interfere with mating, and various scented
plant extracts that attract insect pests to traps).
Pesticide & Residues- Definitions
• Biocide by definition is any substance used with the
intention of killing living organisms whether these are
pests or not.
• Pesticides are compounds that man uses to control,
meaning to reduce in number or to eradicate, organisms
that interact negatively with his activities such as crop
production and gardening, or to control disease in people,
animals, etc.
• Pesticide Residues
Any substance or mixture of substances in food for man or
animals resulting from the use of a pesticide including any
specified derivatives, such as degradation and conversion
products, metabolites, reaction products and impurities
considered to be of toxicological significance.
Toxicity Labelling
Label
Name
Level of
toxicity
Oral lethal dose
mg per kg body
weight of test
animal
Red label
Extremely
toxic
Yellow
label
Highly toxic 51-500
Endosulfan, carbaryl,quinalp
hos, and others.
Blue label
Moderately
toxic
501-5000
Malathion, thiram,glyphosat
e, and others.
Green
label
Slightly
toxic
More than 5000
Mancozeb, oxyfluorfen,
mosquito repellant oils and
liquids, and most other
Wikipedia
household insecticides.
1-50
Listed chemicals
Monocrotophos, zinc
phosphide, ethyl mercury
acetate, and others.
Insectide
• Classification by chemical group
–
–
–
–
Organo Chlorine
Organo Phosphate
Carbamates
Pyrethroids
Organochlorine
• Organic compound containing at least one covalently bonded atom of
chlorine (the diphenylethanes, the cyclodienes and the Cyclohexanes)Highly Effective against various Insects
• High persistence and Highly lipophilic
DDT
Dicolfol
Methoxychlor
X-Cl
X=Cl
X=OCH3
Y=H
Y=OH
Y=H
Aldrin
Dialdrin
& Endrin
Endosulfan
Lindane
Organophosphate
•
•
•
acetylcholinesterase (AChE) in ganglia and in the parasympathetic nervous system.
[SLUD Syndrome]
Highly Toxic , Less lipophilicity, Fast degradation
Parathion (parathion-ethyl) introduced in 1944 -higher environmental stability LD
50:3–13 mg kg−1BW
Ref,
Mello et al., 2003 : Food Safety:
Comtaminants and toxins
Common
name
Rat oral LD50
Rabbit dermal
LD50
Chlorpyrifos
96–270
2,000
Diazinon
1,250
2,020
Dimethoate
235
400
Ethoprop
61.5
2.4
Fenamiphos
10.6–24.8
71.5–75.7
Malathion
5,500
>2,000
Methamidopho 13 (female
s
only)
122
Methyl
45
6
Carbamates
• Low toxicity/ Low Lipophilic
• Acetylcholineesterase
Inhibitor (Reversable)
•
Common
name
Rat oral LD50
Rabbit dermal
LD50
Aldicarb
1
20
Carbaryl
500–850
>2,000
Carbofuran
8
>3,000
Fenoxycarb
16,800
>2,000
Methiocarb
60–1,000 depending on
product
>2,000 (rat)
Methomyl
30–34
>2,000
Oxamyl
5.4
2,960
Thiodicarb
66
>2,000
Pyrethroids
• Pyrethroids~ Pyrethrin (Tanacetum cinerariaefolium)
Common name
DeltametrinLD50 for the fly
is 0.0003 µg
Rat oral LD50
Rabbit dermal LD50
Allethrin
860
11,332
Bifenthrin
375
>2,000
Cyfluthrin
869–1271
>5,000 (rat)
Cyhalothrin
79
632 (rat)
Cypermethrin
250
>2,000
Deltamethrin
31–139 (female)
>2,000
Esfenvalerate
451
2,500
Fenpropathrin
70.6–164
>2,000
Fluvalinate
261–282
>20,000
Permethrin
430–4,000
>2,000
Benzoylureas
• Synthesized between dichlobenil derivatives and
fenuron
• Act on the formation of chitin,hindering the
development of larvae during moult (by causing
the imperfect formationof the new cuticle) and
causing their death.
• They are not selective , affect CNS of mammals.
• Eg., Diflubenzuron, Flufenoxuron, Hexaflumuron
Fungicides
• Inorganic FungicidesCopper Salts
• Organic Fungicides in
Table
• DithiocarbomatesEthyle
ne thio urea
• Benzimidazoles- Systemic
Fungicide
• Dicarboximides- Resistant
• Triazoles - biosynthesis of
ergosterol
• Anilinopyrimidines- Act on
biosynthesis of AA
Ref,
Mello et al., 2003 : Food Safety:
Comtaminants and toxins
Herbicides
• mechanism of action of
herbicides is an
interaction with the
biochemical processes
of vegetables, they have
no toxicity for animals,
But
• Dermitis
• Paraquat- Toxic to lungs
• Percolate into soil
Ref,
Mello et al., 2003 : Food Safety:
Comtaminants and toxins
Maximum residue levels (MRLS)
• Mrl is the highest level of a pesticide residue that is legally
tolerated in or on food or feed when pesticides are applied
correctly (Good Agricultural Practice).
• Mrl covers the safety of all the consumers i.e children to
adults
• The maximum residue levels information is provided by the
chemical produce during chemical registration.
• Any food or non-food should meet the levels of pesticide mrl
of the different pesticides
138
Example of MRL analysis on grapes
139
Extraction process
• This is a fundamental process in pesticide residue
analysis because no in-situ technique has yet been
invented.
• There are several extraction approaches employed such
as:
 Pressurized liquid extraction(PLE)
 Supercritical fluid extraction (SFE)
 Aqueous extraction
 Microwave-assisted extraction(MAE)
 Solid-phase extraction (SPE)
 Solid-phase microextraction (SPME)
 Matrix solid-phase dispersion (MSPD)
140
Clean-up
 Clean-up is done to obtain uncontaminated products
for analysis.
 The clean-up process is vital especially in analysis of
fatty foods.
 Liquid-liquid and liquid-solid partitioning in which
separation is based on polarity is the primary mean of
clean-up in residue analysis.
 Separations based on molecular weight, gelpermeation or size-exclusion chromatography is
common clean-up technique.
 Other techniques used include precipitation,
centrifugation, ultrafiltration, dialysis and
141
immunochemical.
Gel permeation chromatography
• Also known as size-exclusion
chromatography (SEC) separates
compounds with large molecular
weight such as lipids and proteins
from smaller analytes such as
pesticides using a porous stationary
phase material.
142
Analysis
• Capillary electrophoresis
Small amount of sample is typically sucked or forced
into the capillary by pneumatic pressure, then the
voltage is applied.
Separation of ions occurs based on the mobility of
ions, which is a function of size and charge.
Smaller cations in the buffer have higher mobility
and force overall flow toward the anode.
Neutral molecules are carried with this flow in the
electro-osmotic front while charged molecules
migrate faster or slower through the capillary based
on their charge and mobility.
143
Gas-liquid chromatography GC-MS
 GC-MS is usually used in the analysis of mid- polar to
non-polar compounds whereas HPLC technique used
for polar compounds.
 Organophosphate and carbamate pesticides are mid
polar in nature thus gas chromatography is well
suited for their analysis.
 GC-MS systems are equipped with extensive mass
spectral “libraries”that can be extremely useful for
identification and characterization of unknown
compounds.
144
Example of final GC data
obtained
Source : www.restek.com
145
Pesticides detected using GC
Pesticides analysed using GC
 Organochlorines e.g. dieldrine, DDT, Lindane.
 Organophosphorus e.g. diazinon, dichlorvos, malathion
 Pyrethroids e.g. cypermethrin, deltamethrin
 Aromatic fungicides eg chlorothalonil, quintozene
 Dicarboximide fungicides eg folpet
• Other pesticides also analyzed using GC but showing
low or no response include:
 Carbamates, imidazoles, benzoylureas, sulfonylureas
146
Pesticides analysed using LC
Carbamates e.g. carbendazim
Conazoles e.g. fenamidone
Sulfonylureas e.g. triasulfuron
Triazines e.g. simazine
Phenylureas e.g. linuron
Strobilurins e.g. azoxystrobin
Neonicotinoids e.g. acetamiprid
All the above plus their metabolites can be
analysed by Liquid chromatography
147
Mass spectrometry
• Ideally suited for multiresidue analysis
• Features of MS
Universal and selective
Screening and confirmation
Compatible with GC and LC
148
Food Adulteration
Lecture 5
•
•
•
•
Definition of adulteration
Types of adulteration
Common foods adulterated
How to detect adulteration
Introduction
Food adulteration consists of a large number of practices, e.g., mixing, substitution,
concealing the quality, putting up decomposed food for sale, misbranding or giving
false labels and addition of toxicants.
The ignorance of people being not able to recognize food that is wholesome versus
adulterated has made such adulteration possible. Food adulteration can be:
• Economic adulteration implies that food is adulterated by dilution (adding water to
milk), removal (removing 11% fat from food and using 2% fat), or using substitutes
(using Equal for sugar).
• Adulteration also results from addition of foreign material to food, such as stones
in rice to compensate for weight. This addition increases the volume of trade.
• Adulteration can also occur because of the type of package used for holding food.
Labeling should disclose the integrity of the food, and if adulterated food is labeled
as one that is not, then unaware consumers are injured or harmed by consuming
such food. Packaging and labeling are more recent developments, and newer laws
have been instituted to discourage food adulteration.
ADULTERATION
Simple definition:
Reducing the purity of an article by the addition
of a foreign or inferior substance
 Act of intentionally debasing the quality of food offered for
sale either by admixture or substitution of inferior substances
or by the removal of some valuable ingredient.
What is Adulteration?
• An adulterant is a chemical substance which
should not be contained within other substances (e.g. food,
beverages, and fuels) for legal or other reasons.
• The addition of adulterants is called adulteration.
• The word is appropriate only when the additions are
unwanted by the recipient. Otherwise the expression would
be food additive. Adulterants when used in illicit drugs are
called cutting agents, while deliberate addition of toxic
adulterants to food or other products for human consumption
is known as poisoning.
What is Adulteration??
• Adulteration usually refers to mixing other matter of an
inferior and sometimes harmful quality with food or drink
intended to be sold. As a result of adulteration, food or drink
becomes impure and unfit for human consumption.
• "Adulteration" is a legal term meaning that a food product
fails to meet federal or state standards.
Food adulteration is defined as ‘the
intentional addition of non-permitted
foreign matter’.
Reasons for food adulteration are
To get more profit
To increase the weight, adulterant is
added.
To increase volume of trade by showing
lower prices.
Food is said to be adulterated if…
• the article sold by a vendor is not of the nature, substance or
quality demanded by the purchaser;
• the article contains any other substance which affects the
nature, substance or quality;
• any inferior or cheaper substance has been substituted;
• the article had been prepared, packed or kept under
insanitary conditions whereby it has become contaminated or
injurious to health;
• the article consists wholly or in part of any filthy, putrid, ,
rotten, decomposed or diseased animal or vegetable
substance or is insect-infested or is otherwise unfit for human
consumption;
• the article is obtained from a diseased animal;
• the article contains any poisonous or other ingredient which
renders it injurious to health;
• the container of the article is composed of any poisonous or
deleterious substance which renders its contents injurious to
health;
• any coloring matter other than that prescribed is present in
the article;
• the article contains any prohibited preservative or permitted
preservative in excess of the prescribed limits;
Different Types of
Food Adulteration
 Intentional: Sand, marble chips, stones, mud, other filth,
talc, chalk powder, water, mineral oil
 Incidental: Pesticide residues tin from can, droppings of
rodents, larvae in foods.
 Metallic contamination: Arsenic from pesticides, lead from
water, mercury from effluent, from chemical industries, tins
from cans.
 Packaging Hazards: Polyethylene, polyvinyl chloride and
allied compounds are used to produce flexible packaging
material.
Some Adulterated Foods in market
Turmeric, dals and pulses
• Adulterant: Metanil Yellow and Kesari Dal
• Health hazard: highly carcinogenic, stomach
disorders.
Green chillies, green peas&other vegetables
• Adulterant : Malachite Green, Argemone seeds
• Health hazard: carcinogenic if consumed over a long
period of time
Mustard seeds and mustard oil
• Adulterant : Argemone seeds, Papaya seeds
• Health hazard: epidemic dropsy and severe
glaucoma
Some other adulterants…
 Cream is adulterated with gelatin, and
formaldehyde is employed as a
preservative for it.
 Butter is adulterated to an enormous
extent with oleomargarine, a product of
beef fat.
 Brick dust in chilli powder, colored chalk powder in turmeric.
 In confectionery, dangerous colors, such as chrome yellow,
prussian blue, copper and arsenic compounds are employed.
 Pickles and canned vegetables are sometimes colored green
with copper salts.
Common adulterants present in food:
Milk - Addition of water/removal of fat.
Skim milk - soluble starch.
Cream -foreign fats.
Vegetable oils -Cheap/non edible oil like
linseed, mineral oils.
Wheat and rice -stones
Chilli powder- Starch colored red by tar
dye.
Black pepper- Dried papaya seeds
Honey -colored sugar syrup.
Tea - exhausted tea leaves.
055
ADULTERATED MILK
Milk is generally adulterated with either water or by starch
MATERIALS REQUIRED
Milk samples
Dropper
Black paper
Tincture iodine (available in Pharmacy)
milk
NORMAL ADULTERANT TO MILK IS WATER
PURE MILK WILL FLOW SLOWLY
AND LEAVE A WHITE TRAIL.
ADULTERATED MILK WILL FLOW FAST
AND NOT LEAVE A WHITE TRAIL
If milk is contaminated by starch
then add a drop of tincture iodine to warm milk
milk
adulterated
milk
no change
in colour
changes in
colour to blue
Foods Commonly Involved
Honey
• Invert sugar/jaggery
Test
•
Aniline Chloride Test : Take 5 ml. Of honey in a porcelain
dish. Add Aniline Chloride solution (3 ml of Aniline and 7
ml. Of 1:3 HCl) and stir well. Orange red colour indicates
presence of sugar.
Foods Commonly Involved
Wheat flour
Adulterants in food
Diseases or Health Effects
• Chalk powder
Test
• Shake sample with dil.HCl Effervescence indicates
chalk.
Some adulterated food products and
there adverse effects
•
Turmeric, dals and pulses such as moong or channa: Here
adulterant is Metanil Yellow and Kesari Dal (Added to
enhance the yellow colour of a food substance).It's harmful
effect is that it is highly carcinogenic and if consumed over a
continuous period of time it can also cause stomach disorders.
•
Green chillies, green peas and other vegetables: Here
adulterant is Malachite Green (To accentuate the bright,
glowing green colour of the vegetable).Argemone seeds (used
to add bulk and weight)that it is a coloured dye that has
proven to be carcinogenic for humans if consumed over a
long period of time.
Some Examples
Adulteration in olive oil
Contd…
• Mustard seeds and mustard oil: Here adulterant is Argemone
seeds (used to add bulk and weight).Papaya seeds (used to add
bulk)that the consumption of these could cause epidemic
dropsy and severe glaucoma. Young children and senior
citizens with poor immunity are more susceptible this.
• Paneer, khoya, condensed milk and milk: Here adulterant is
starch (used to give itthick, rich texture).It 's harmful effect is
that it is unhygienic, unprocessed water and starch can cause
stomach disorders. Starch greatly reduces the nutritional value
of the ingredient.
Contd…
• Ice cream: Here adulterant is pepperonil, ethylacetate, butraldehyde,
ethyl acetate, nitrate, washing powder etc which are not less than
poison. Pepper oil is used as a pesticide and ethyl acetate causes
terrible diseases affecting lungs, kidneys and heart.
• Black pepper: Here adulterant is Papaya seeds (used to add bulk).It
's harmful effect is that Papaya seeds can cause serious liver
problems and stomach disorders.
•
Coffee powder: Here adulterant is Tamarind seeds, chicory powder
It 's harmful effect is that it can cause diarrhea, stomach disorders,
giddiness and severe joint pains
How to Detect Adulteration
• Ingredient : Coffee powder, Adulterant: Cereal starch
Take a small quantity (one-fourth of a tea-spoon) of the sample in
a test tube and add 3 ml of distilled water in it. Light a spirit lamp
and heat the contents to colourize. Add 33 ml of a solution of
potassium permanganate and muratic acid (1:1) to decolourize
the mixture. The formation of blue colour in mixture by addition
of a drop of 1% aqueous solution of iodine indicates adulteration
with starch.
Images showing Detection of Adulteration
Contd…
• Ingredient : Black Pepper, Adulterant: Papaya Seeds
Papaya seeds do not have any smell and are relatively smaller
in size. Adulteration of papaya seed with Black Pepper may
be detected by way of visual examination as also by way of
smelling.
 Ingredient : Coriander powder , Adulterant: Saw Dust
Take a little amount (a half of tea-spoon) of the sample.
Sprinkle it on water in a bowl. Spice powder gets sedimented
at the bottom and saw-dust floats on the surface.
An Article on Food Adulteration
Contd…
• Ingredient : Green vegetables like Bitter Gourd, Green
Chilly and others, Adulterant: Malachite Green
Green vegetables like Bitter Gourd, Green Chilly and others
Malachite Green Take a small part of the sample and place it on
a piece of moistened white blotting paper. The impression of
color on the paper indicates the use of malachite green, or any
other low priced artificial color.
 Ingredient : Rice, Adulterant: Earth, sand, grit, unhusked
paddy, rice bran, talc, etc.
These adulterants may be detected visually and removed by way
of sorting, picking, and washing.
COMMON ADULTERATES
 Addition of chalk to flour
 Added water can be an adulterant
 Addition of colors to disguise poor quality
 Addition of sand to brown sugar and rice to make
heavier
 Addition of sand to brown sugar and brown rice