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Microbial Hazards
Preeti Malik
Microbial Hazards
Microorganisms are everywhere -- they can be:– Pathogens – cause disease– Spoilers – cause the quality of food to deteriorate– Beneficial – used for food production and
present in and on the body
Types of Food borne Illness
Infection› eating food contaminated with pathogens
Intoxication› eating food contaminated with the toxins (poisons)
formed by bacteria › eating food contaminated with other biological or
chemical toxins (poisons) Toxin-mediated infection
› eating food contaminated with pathogens that grow in the body and form toxins (poisons)
Three Microbial Hazards
Three microorganisms cause most food borne illness: Bacteria Viruses Parasites
Microorganisms are: naturally present or get into the food through poor handling practices.
Common Symptoms
Common symptoms of food borne illness are:
› diarrhea› vomiting› fever› sore throat with fever› jaundice
Bacteria Basics Invisible to the naked eye. Pathogenic bacteria only grow in potentially
hazardous food, which are also called TCS food. Some produce spores. Some produce toxins. Not necessarily destroyed by freezing or cooking. Can cause infection, intoxication, or toxin-
mediated infection.
Conditions for Bacterial Growth
Potentially hazardous food› Low acid (pH >4.6)› Moist› Protein
Time › 4 hours or longer in the temperature danger zone
Temperature › Between 41oF and 135oF
Activity
Oxygen
Some pathogenic bacteria require oxygen; others do not.
Clostridium botulinum grows in the absence of oxygen.
Absence of oxygen may occur in: Vacuum packaged food Center of thick cooked foods, such as stew Garlic in oil that is not commercially processed Foil wrapped potatoes Cooked rice
Controlling BacteriaGood personal hygiene
›Only allow healthy workers to handle food.›Have all workers wash their hands properly
and frequently.Prevent cross-contamination
›Store foods properly. ›Only use cleaned and sanitized utensils and
surfaces for food preparation.Time-temperature control
›Cook foods to proper temperatures.›Hold foods at proper temperatures.
Common Food borne Bacteria
Bacillus cereus Campylobacter Clostridium
botulinum Clostridium
perfringens E. coli Listeria
monocytogenes
Salmonella Shigella Staphylococcus
aureus Vibrio Yersinia
Virus Basics
Do not grow in food; use food as a vehicle to get from one person to another.
Can contaminate any food. Cause most foodborne illnesses in the U.S. Invisible to the naked eye Cause foodborne infection not foodborne
intoxication.
Controlling Viruses
Prevent getting viruses into food because they might not be destroyed by cooking.
Prevent introduction by: Only allowing healthy workers to handle food. Having all workers frequently and properly wash their
hands. Buying all food from an approved and safe source.
Common Foodborne Viruses
Hepatitis A
Norovirus
Thank you