Download section 6 6.0 food and consumer health

FST 201: INTRODUCTION TO FOOD
TECHNOLOGY
SECTION 6
FOOD AND CONSUMER HEALTH
DR MRS. J. M. BABABJIDE
Introduction
Consumer health can be defined in terms
of what people consume in order to be
healthy.
Food is what we consume to give us
nutrients for growth, sustenance and
replacement of worn out tissues.
Food with little or no nutrients, incomplete nutrients
when consumed on a regular basis will result into bad
health such as growth retardation, sicknesses, loss of
body immunity against diseases etc
Food with contaminants are deleterious to human
health
Over processed food will lead to loss of protein and
vitamin
Regular consumption of food with only carbohydrate
leads to a condition called kwashiorkor
Lack of enough supply of energy results in a
protruded belle, thin arms and legs or swollen body in
a condition called marasmus.
Toxicants of Foods
A toxicant is any chemical substance that can
elicit a detrimental effect in a biological system. Food
toxicant can be divided into three categories, namely
endogenous, naturally occurring and synthetic.
1. Endogenous Toxicants
substances produced by tissue cells in plants and
other biological raw materials.
chemical substances often serve the purpose of
protecting plant tissues from pests, as well as from
pathogenic organisms
Transmission to man can be direct
consumption of toxic plants or from
animals who have consumed the plant that
are then used for human foods
Examples include flavonoids, goitrogens,
coumarins, cyanogenic compounds, herbal
extracts, and mushroom toxins.
2. Synthetic toxicants
 They are those that are synthetically produced,
which found their way into our food supply
through contamination of the food processing
environment.
e.g
pesticides,
additives,
preservatives
 Pesticides
include insecticides, herbicides,
rodenticides, fungicides, fumigants etc.
 Amide herbicides (propanil) which is used
extensively to control harmful weeds in rice crops
could cause liver damage, central nervous system
depression and death.
A new method of pest management (Integrated
Pest Management-IPM) which is based on the
minimal use of chemical pesticides to control
insects was introduced in the 1980s. IPM seeks to
integrate several techniques to control insects
and other pests, instead of relying solely on
chemicals.
The concentration of residues that can be found in
foods produced from treated crops is being
regulated (maximum residue levels-MRL) in such
a manner that strict compliance is demanded.
3. Naturally occurring Toxicants
 They are those produced by organisms that
contaminate the food products.
 Microorganism such as dinoflagellates, fungi,
and bacteria can produce toxicants that upon
consumption can cause diseases.
 Some toxin-producing organisms produce toxins
in the food matrix (which can cause intoxication
if consumed), while others produce toxins inside
the victim (intoxification).
 some able to withstand heating temperature
used in cooking, while others are able to tolerate
extremes of pH without losing activity.
Some of these Micro organisms cause very serious
diseases
such
as
typhoid,
dysentery,
salmonellosis, cholera and food intoxications.
They are generally specific depending upon the
type of food and particular conditions of storage.
e.g moulds (Aspergillus) are commonly associated
with cereal product spoilage, Lactic acid bacteria
(Lactobacillus) spoils raw milk and yeasts
(Saccharomyces) spoil fruit juice when stored
under unfavourable conditions.
The
undesirable
changes
caused
by
microorganisms can be divided into: those
that cause food spoilage not usually
associated with human disease and those
that cause food poisoning which could be:
i. food infection,
ii. food intoxication or
iii. food intoxification.
i. Food infections are caused by
disease organisms which are carried
to the host through foods; they
multiply in the intestinal tract,
vaginal trud etc and cause diseases
through infection of their tissues.
Examples of these diseases are cholera,
salmonellosis,
shigellosis,
ameobiosis.
Cholera is caused by Vibrio comma, transmitted
through drinking water and contaminated food.
The symptoms are diarrhoea, watery stools and
vomiting.
Salmonellosis is caused by salmonella bacteria
transmitted through foods such as meat, egg and
fish. They are easily killed by normal good
cooking, and must be eaten alive in sufficient
number to cause infection.
Symptoms are abdominal pain, diarrhea, frequent
vomiting and occasional death may occur when
untreated.
ii Food intoxication is caused by organisms which grow
in food and produce chemical substances in the food
which is toxic. Examples are
Staphylococcal poisoning, caused by Staphylococcus
aureus.
Symptoms are salivation, nausea, vomiting, diarrhea and
abdominal cramps. Sources of contamination are
mouth, throat, nose through coughs and sneezes.
Botulism which could be very fatal is caused by
Clostridium botulinum transmitted through home
canned foods which are not properly processed.
Symptoms are vomiting, constipation, difficult of eye
movement, difficulty in speaking. Death could result
due to the paralysis of the muscles responsible for
respiration.
iii Food Intoxification: is caused by ingestion of
bacteria that once inside the small intestine,
begin to produce toxin.
The organism E. coli O157:H7 is a good example
of this type of pathogen, able to produce
toxin after damaging the lining of the
intestine. These toxins are absorbed by the
body, reaching the kidneys where they cause
substantial damage to the convoluted
tubules.
In addition to serotype O157:H7, other
enterohemorrhagic E. coli serotypes are
O145:H-, O26:H11, O104:H21, and O111:NM.
The following steps could be taken to avoid consumption of
contaminated foods:
 1. Avoid overdose use of pesticides or preservatives such as
sodium benzoate.
 2. Samples of food crops or food product should be tested for
residual pesticides or preservatives by appropriate agencies
e.g. NAFDAC to ensure safety before they are distributed to
the market for consumers.
 3. In preparation of foods, simple unit operations such as
peeling/dehulling, soaking, dewatering, boiling, roasting and
drying could get rid of the natural food toxins and
antinutritional constituents to insignificant levels when
properly done.
 4. Properly cooked food before consumption will prevent food
poisoning by microorganisms.
 5. Good hygiene, good handling of food to avoid
recontamination after cooking and proper storage of food
before consumption (Good Manufacturing Practices)
Risk Assessment for Biological Hazards
Risk assessment refers to the determination of the
risk posed by an entity or situation to a population.
To carry out risk assessment of biological hazards,
there is need to determine the probability of risk. In
this method, the probability, or likelihood, of an
adverse event occurring due to consumption of a
biological hazard is determined. In addition, the
magnitude, or severity, of the risk, even if unlikely
to happen, is taken into consideration.
To carry out a risk assessment of biological
hazards, the following steps is carried out:
 1. Identify and characterize the hazard (is it
bacterial, viral, etc?)
 2. Assess the dose required (number of
microorganisms) necessary to produce
illness.
 3. Assess the exposure of the population to
the particular biological hazard (prevalence
of the organism in a particular food).
In
conducting a risk assessment, several
mathematical models of probability can be
used. The most common is the Poisson
distribution, expressed as:
P = 1 - e¯RN
where P= probability (in percentage) of infection
with a food borne pathogens, also known as
the risk; R is a constant specific to a particular
pathogen, based on its growth characteristics,
also known as the probability of getting sick if
one cell of the pathogen is consumed; and N is
the number of cells of the pathogen present in
a particular food.