Download statistics of food-borne microbial disease

FOOD BORNE
MICROBIAL DISEASE
OUTLINE
DEFINITON
STATISTICS OF FOOD-BORNE MICROBIAL DISEASE
VIRAL DISEASE AND FOODS
TOXIGENIC FUNGI IN FOODS
DEFINITION
• Food-borne illness arises through the consumption of a food
contaminated with a pathogenic species. The food ray serve in
two capacities in this food-microorganism-man interaction:
foods as vectors of patogens
foods as substrates for patogenic growth
 Foods as vectors of patogens
• Micro-organisms associated with these cases generally have a low
infective dose ie. only a very small number of the pathogen cells
(<100) need to be consumed to bring about a consumer response or
reaction. These include typhoid (Salmonella typhi), dysentery
(Shigella dysenteriae), cholera (Vibrio cholera) and tuberculosis
(Mycobacterium).
 Foods as substrates for patogenic growth
• Foods act as substrates for the growth and multiplication of pathogenic Species.
Which when developed to high enough numbers, cause ilIness on human
consumption. These are the Classical cases of microbial based food Poisoning.
Two sub-groupings may be recognized.
1. Consumer infection: Upon consumption ion the pathogenic species
concerned multiplies in the alimentary tract thereby bring about consumer
response or reaction. (Salmonella species. Clostridium pefringens. Vibrio
parahaemolyticus, enteropathogen Escherichia coli strains and Shigella
species).
2. Consumer intoxication: In this case it is the consumption of a toxic
product previously produced in the food by microbial growth which
brings about a consumer response. (Staphylococcus aureus and
Clostridium botulinum).
STATISTICS OF FOOD-BORNE
MICROBIAL DISEASE
• Food poisoning statistics require the following three pieces of
information :
The causative food
The origin of the causative food, and
The nature of the causative organism.
• Statistics gathered in the U.K., U.S.A. and Australia have continually
shown that approximately 70% of all food poisoning outbreaks are
associated with the consumption of meat and poultry products. Sea
foods contribute to another of the outbreaks while egg and dairy
products are responsible for around.
Virusal Disease and Foods
• Viruses, unlike bacteria, cannot reproduce outside a living host
cell.
• Viruses pathogenic to men cannot reproduce in a food so that
there can never be more viruses in a food than were introduced at
the time of contamination.
• Offsetting this inability of viruses to multiply to large numbers in
the food is their generally low infective dose.
• Because of their more simple chemical, physical and biological nature,
viruses are quite often more resistant to food processing and storage
stresses than bacteria.
• Consequently, food processing operations designed to eliminate
pathogenic bacteria may not necessarily kill viral contaminants.
• The technology for viral detection in foods is only in the
developmental stages and is mainly based upon physical and chemical
methods.
Toxigenic Fungi in Foods
• Moulds have not only served to synthesize antibiotics but also to
produce some foods.
• Moulds also cause food spoilage but this spoilage has usually been
considered as unaesthetic rather than being dangerous to consumer
health.
• . In fact, it is now well established that many fungi, on contamination
and growth in food products, produce toxic substances generally
termed mycotoxins.
• A mycotoxin has been defined as fungal metabolite producee in
foodstuffs (or feedstuffs) that causes illness or death when ingested by
man or animals.
Mycotoxins of Possible Human Health Significance
• Control of mycotoxins in foods is best achieved by preventing mould
contamination and subsequent mould growth.
• Not all moulds are known to produce mycotoxins.
• Mycotoxin presence in foods can be determined by chemical
extraxtion from the food followed by identification of the mycotoxin
using chromatographic procedures.
Possible Routes for Mycotoxin Contamination of Human Foods