I WELCOME YOU ALL TO THIS PRESENTATION ON MICROBIAL FOOD CONTAMINATION MR ABU GBLA PRESENTATION

MAIN OBJECTIVES IN THIS PRESENTATION  MICROBIAL FOOD CONTAMINATION  TYPE OF MICROBIAL CONTAMINATION IN FOOD  FACTORS AFFECTING THEIR GROWTH  CONTROL MEASURE

MICROBIAL CONTAMINATION The growth of undesirable microorganisms in food like bacteria, viruses, fungi, yeast, and parasites.

Microbial contamination of food is the most important cause of foodborne illness. Foodborne disease can be defined as any disease usually either infectious or toxic in nature, caused by an agent that enters the body through ingestion of food. Foodborne diseases are the worldwide problem of human suffering and economic cost.

TYPES OF MICROBIAL CONTAMINATION Parasites Viruses Bacteria Fungi Causes of foodborne illness

However based on the type of effect these microbes do on us and animals, they can be categorized into two groups: 1.Spoilage microorganisms 2.Pathogens Spoilage microorganisms affect the quality of food while pathogens caused foodborne illnesses.

WHAT IS FOOD SPOILAGE? -Food spoilage is undesirable changes that have taken place in food (like appearance, texture, odor, flavor and slime formation) which have made it unfit to eat. - Deterioration of food caused by natural decay or contamination with microorganisms INDICATION FOR FOOD SPOILAGE  Presences of foreign bodies  Organoleptic changes  Physical damage  Freezer burn

 Over-ripe fruits and vegetables  Staling  Chemical contamination Bacteria They are single celled organisms They may be carried by food, water, humans or insects

Some species of bacteria that Causes foodborne illnesses

VIRUSES They are ultramicroscopic living entities They are the smallest among all the microbial contaminants Virus always needs a living cell for its multiplication

Viruses can be transmitted from person to person, from people to food and also from people to food contact surfaces. They usually contaminate the food through improper food handlers, and lack of personal hygiene. Bare hand contact should be avoided with ready to eat food to control foodborne virus contamination

PARASITE Parasites are the living organisms that are dependent on a host (man, plant or animal) for their survival. Parasite takes nourishment from these living hosts.

Parasites may be transmitted from host to host through consumption of contaminated food and water or by putting anything into your mouth that has touched the stool (faeces) of an infected person or animal. Some species of parasite that causes foodborne illnesses

FUNGI Fungi are microscopic single celled organisms, others are multicellular and saprophytic living entities. They are naturally found in air, soil, plants, animals, water and some foods

Molds are multicellular in nature and can grow on almost any substance used for food if the conditions are favorable for growth. Some molds produce toxins in the food which are known as mycotoxins.

Food with molds that are not a natural part of the product should always be discarded. Some species of fungi that causes foodborne illnesses

FUNGAL TOXINS Aflatoxins- is the most important mycotoxin which is produced by Aspergillus species of fungi like A. Flavus and A. Parasiticus. -The four different types of aflatoxins produced by Aspergillus are B1, B2, G1 and G2. Ochratoxin- is a mycotoxin produced by Penicillium and Aspergillus species. -Ochratoxin comes in three secondary metabolite forms such as A, B, and C - Aspergillus ochraceus is a contaminant of wild range of commodities such as coffee, beer and wine.

YEASTS Yeasts are single celled organisms and as they grow convert its food to alcohol and carbon dioxide (CO2). Yeast spoilage may therefore produce a smell or test of alcohol. Yeast may appear as a pink discoloration or slime and may bubble

FACTORS RESPONSIBLE FOR MICROBIAL GROWTH IN FOOD These factors are grouped into:  Intrinsic factors such as  composition  PH  Oxidation and reduction potential  Antimicrobial chemical like, lactoferrin in fresh milk, lysozyme in egg white, benzoic acid in cranberries.

 Presence and availability of water  Physical structure

 Extrinsic factors  Temperature  Relative humidity  Microorganisms  Atmosphere

SOURCES OF MICROBIAL CONTAMINATION IN FOOD  Soil and water  Air and dust  Plant and plant product  Food utensil  Food handlers  Animal feed and hides

CONTROL MEASURES FOR THE GROWTH OF MICROORGANISMS 1.Freeze food to retard growth of microorganisms and inhibit enzyme activity e.g. frozen food. 2.Heat food to destroy microorganisms and prevent enzyme activity e.g. pasteurized milk. 3.Place food in salty solution to make water unavailable to microorganisms e.g. pickled vegetables. 4.Place food in sugary solution to make water unavailable to microorganisms e.g. Jam.

5. Keep food in airtight containers to deprive microorganisms of oxygen and prevent further contamination e.g. Canning. 6. Modifying the atmosphere in the packaging of a food product e.g. meat product, potato chips. 7. Reduce moisture content of food. 8. Use fermentation to produce food products with extended shelf life e.g. milk to cheese. REFERENCES e%20publikationer/ pdf contamination

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