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