Food safety

What is in food?



  • Over 40,000 cases are reported in the U.S. every year
  • Commonly found in the intestines of humans, dairy animals, reptiles, and birds.
  • Transmitted through contaminated food and contact with fecal matter



  • One of the most common foodborne illnesses
  • Shigella is also known as bacterial dysentery
  • The four species include sonnie, flexeri, dysenteriae, and boydil
  • This bacteria lives in the intestines
  • Over 14,000 cases are reported to the CDC every year
  • Follows a fecal-oral route
  • Commonly seen in toddlers who are potty training
  • Can be transmitted through contaminated food
  • Can be transmitted by flies carrying fecal matter to food
  • People with shigellosis should not prepare food or drinks

Clostridium Botulinum

Clostridium Botulinum

  • Produces heat resistant, paralyzing neurotoxin
  • Botulism: paralytic disease caused by the bacterial neurotoxin when it is ingested
  • The most poisonous substance in the world
  • Cases are rare but high mortality rate if left untreated
  • Grows in anaerobic environments (free of oxygen) such as canned foods
  • Most cases reported in the U.S. caused by improperly home-canned foods
  • Does not spread from person to person
  • CDC: boil home-canned foods for 10 minutes before consuming, though heat will not destroy the neurotoxin


  • Common bacteria that cause foodborne illness:
  1. Salmonella
  2. Campylobacter
  3. Shigella
  4. Escherichia coli (E. coli)
  5. Clostridium Botulinum
  6. Vibrio
  7. Listeria Monocytogenes
  8. Clostridium Perfringens

Listeria monocytogens

Listeria Monocytogenes

  • Can grow in low temperatures (in the refrigerator)
  • Approximately 500 out of the 2,500 people infected every year with Listeria die
  • Most of the deaths include individuals who are considered high risk
    • Pregnant women
    • Newborns
    • Elderly
    • Immunocompromised
  • Susceptible foods include:
    • Vegetables fertilized with manure
    • Raw and unpasteurized food and dairy products
    • Smoked seafood
    • Deli meats

Danger zone

All food bacteria are capable of rapid growth at the 41°F - 135°F (5°C - 57°C) range. This range of temperatures is called the Danger Zone. Never thaw items at room temperature. Always thaw frozen items in a refrigerator close to 38°F (3°C). Some items can be thawed under cold running water. Always check with a supervisor if you are not sure. One rule of thumb to remember is that food bacteria are like people in one respect; the temperature they enjoy most is between 60°F - 90°F (16°C - 32°C). Bacteria grow rapidly in the Danger Zone. Therefore, foods should never be warmer than 40°F or colder than 135°F.

Under optimal conditions, E. coli, for example, can double in number every twenty minutes. The food may not appear any different or spoiled but can be harmful to anyone who eats it. Meat, poultry, dairy products, and other prepared food must be kept outside of the food danger zone to remain safe to eat. Refrigeration and freezing do not kill bacteria, but only slow their growth. When cooling hot food, it should not be left standing or in a blast chiller for more than 90 minutes.

Hand washing

  1. Wet hands and arms with water as hot as you can stand it (at least 100 degrees F)
  2. Apply soap
  3. Scrub hands, nails, arms for 10-15 seconds
  4. Rinse
  5. Dry hands and arms with single-use paper towel, NOT A RAG OR YOUR APRON!


Do not substitute hand sanitizer for hand washing. Hand sanitizer may be used after hands have been thoroughly washed.

Dangerous chemicals

Chemicals can cause dangerous and poisonous reactions in food. Many times theses accidents are due to negligence in using equipment or unsafe handling of pesticides and polishing or cleaning agents. Some potential chemical hazards include:

  • Antimony: an element in flame proofing compounds used in ceramic enamel that can become a hazard if leaked into food by storing or cooking food with a high acid content in chipped enamelware
  • Copper: found in corroded utensils or some beverage dispensers with copper tubing
  • Cyanide: found in silver polish
  • Lead: can be present in water in lead piping

The impact of chemical contaminants on consumer health and well-being is often apparent only after many years of prolonged exposure at low levels (cancer, for example).

Chemical contaminants present in foods are typically unaffected by thermal processing (unlike most microbiological agents).

Proper food safetey

Proper Food Storage

Although we keep food at different temperatures and in different areas of the kitchen, the ways we store foods in all these areas have a lot in common. All items should be clearly identified and well-wrapped. Storage areas should not be allowed to get so crowded that items are "buried" or lost

Many different kinds of equipment are used for food storage in the commercial kitchen. They include walk-in and reach-in refrigerators and freezers, and dry storage equipment like shelving and bins.

In the kitchen there are basically three categories for food and supply storage: Dry, Refrigerated and Frozen.

What hosts microorganisms

Microorganisms need a host environment in which to split and multiply. Food can be the perfect place!

  • Meats, fish, poultry, eggs, dairy products, sprouts, raw seeds, and even some grains and vegetables are particularly susceptible because they are high in proteins and carbohydrates, which are nutrients that microorganisms need to thrive. They also have high water activity (see Moisture below). Be especially careful with these foods.