Page 2 - ServSafe Manager Study Guide for the ServSafe

Food Contamination

The manager’s primary focus is to prevent foodborne illness, which occurs when food becomes contaminated by something harmful. Contaminants can be biological, chemical, or physical.

The Contamination Process

Most contamination happens accidentally (but it is possible for contamination to happen on purpose). Managers must be aware of contaminants and the ways they come in contact with food. Contamination can come from: the type of foods being used, water, air, dirt, chemicals used near food, a sick or unhygienic employee, pests, etc. Managers must be aware of all types of contamination and the potential sources.

Types of Contaminants

Most contaminants spread to food via the careless food handler, whether by cross-contamination with surfaces or tools, or not washing hands after the restroom and causing fecal-oral route contamination (feces remaining on fingers and passing to foods). Using a cleaner too close to food or leaving bones in a fish filet also causes contamination. Understanding all contaminant types and their sources is a manager’s priority.

Biological Contaminants

Biological contaminants are microorganisms that pass onto food. Harmful microorganisms are known as pathogens, and some make you sick. Biological contaminants include: bacteria, viruses, parasites, and fungi (molds and yeast) and cause the most foodborne illnesses.


Bacteria are all around us. Some are healthy while others cause illness. They’re indiscernible and grow exponentially under the right conditions, but their growth can be slowed (using FAT TOM) or prevented (by minimum internal cooking temperatures).

FAT TOM—We use FAT TOM to help us remember the conditions that promote bacterial growth:

Food (something for the bacteria to grow in)
Acidity (little to no acid. A pH of around 7)
Temperature (the temperature danger zone range, 41°F to 135°F, where bacteria grows rapidly)
Time (the longer in the TDZ the more bacteria will grow)
Oxygen (some bacteria need it, some don’t)
Moisture (the more moisture, the better for bacterial growth)

Common Illness-Causing Bacteria—The FDA identifies Salmonella Typhi, nontyphoidal Salmonella (NTS), Shigella spp., and Shiga toxin-producing E. coli (STEC) as the four most common, highly contagious, severe illness-causing bacteria.


Viruses come from humans or animals and need a living host. They don’t grow in food, but can be passed in food. They can come from water, or anything typically contaminated with fecal matter (employees hands, dirt, etc.).

Major Viruses—The FDA identifies hepatitis A and norovirus as two highly contagious viruses that cause severe illness. Anyone diagnosed with either should not report to work.

Destruction of Viruses—Viruses cannot be slowed or prevented with minimum internal cooking temperatures, so it’s imperative managers and food handlers exhibit good personal hygiene when touching food, work surfaces, tools, etc. Cleaning up vomit quickly is also imperative.


Parasites cannot live and reproduce without a host and are commonly found in seafood, wild game, and foods that are processed with water (produce). Ordering food from reliable sources (especially frozen fish that will be served raw or uncooked) is the best defense against parasites, as well as minimum internal cooking temperatures.


Fungi includes yeasts, mushrooms, and molds. Always throw away moldy foods and buy mushrooms from reliable sources because some mushrooms create harmful toxins.

Biological Toxins

Naturally occurring toxins can be found in some plants, mushrooms, and seafood, and some toxins (histamine) are created when pathogens become time-temperature abused. They can’t be slowed or prevented by cooking, so always purchase these items from approved reputable sources.

Additional Pathogens

There are many other pathogens that can cause foodborne illness beyond the ones mentioned here. The National Restaurant Association or your local regulatory authority can provide a supplemental list of harmful pathogens.

Chemical Contaminants

Chemical contamination occurs when food comes in contact with cleaners, sanitizers, polishes, pesticides, medications, etc. and food should be stored separately from them. Certain materials (zinc, pewter, copper, painted pottery) can also cause chemical contamination and shouldn’t be used for food if not food safe, and should never be used with acidic foods (e.g., tomato sauce).

Physical Contaminants

Physical objects left in or dropped into food are contaminants, like metal shavings, fingernails, staples, bandages, glass, dirt, etc. These could cause mild to fatal injuries like cuts, tooth damage, or choking. Order food from reliable sources, inspect food, and practice good hygiene to prevent physical contamination.

Deliberate Food Contamination

Accidental contamination is very common, but preventing deliberate contamination is also a manager’s responsibility. Someone may try to tamper with food using any of the three types of contamination mentioned above at any point in the food supply chain.


Terrorists, activists, disgruntled staff, vendors, or competitors may try to tamper with food.


Creating a food defense program for your establishment will help identify every point where food is at risk of tampering. The FDA created A.L.E.R.T. (Assure, Look, Employees, Reports, Threat) to help managers identify these food risk points and create a defense plan for their facility.

Actions to Take

  • Assure your food comes from a safe, reliable, and approved source.

  • Supervise all deliveries.

  • Look at your facility’s security.

  • Lock all storage rooms, especially chemicals.

  • Train your staff to spot threats.

  • Limit access** to prep areas.

Employees should know who’s in the establishment and who’s allowed in certain areas. Reports should be kept in relation to the defense plan such as receiving logs. If there is a threat, know what to do and who to contact if suspicious activity happens. Confiscate any suspicious products and contact your local regulatory authority.

Foodborne Illness Response

Even the most well-intentioned certified managers may experience a foodborne illness outbreak in their facility, so it’s important to know what steps to take when and if this occurs.


It is important to get as much information as possible from the person reporting the illness. Get their contact information and the description of the food they ate as well as their symptoms and when the symptoms first started. Document this information.

Local Actions

Remove the suspected food from further use and** label** it “Do Not Use” and “Do Not Discard.” Document the removed product with information such as: production date, lot number, sell-by date, pack size, etc. Review receiving logs to identify which employees handled the item(s) so they can be interviewed in regard to their own health.

Working with Authorities

Contact your local regulatory authority and cooperate with their investigation. Give them your documentation, as well as any temperature logs, HACCP documents, staff logs, etc. Review your receiving, storing, handling, holding, cooking, and serving procedures to identify what procedure is not being met or not working.

Additional Terms and Concepts to Study:

  • Measuring Food Temperature

  • Cooking to Internal Food Temperatures

  • Storage Safety

  • Chemicals

Food Allergens

Allergens are naturally occurring food proteins some guests have sensitivities to, and when eaten in high numbers cause an allergic reaction. An allergic reaction is triggered by immune system responses to what your body perceives as a threat, attacking the protein. Managers should be familiar with the most common foods associated with allergic reactions and how to spot them.

Common Symptoms of an Allergic Reaction to Food

Allergic reactions may happen immediately or hours later, and may include: nausea; wheezing or shortness of breath; swelling of face, eyes, hands, feet, etc.; hives or red, bumpy, itchy rashes; vomiting; diarrhea; abdominal pain; and itchy throat. These symptoms can range from mild to serious to severe (such as anaphylaxis, which can lead to death). Call emergency services immediately if someone exhibits these symptoms.

Common Food Allergens

Over 160 different foods can cause allergic reactions, but eight foods make up 90% of reactions reported. These are the Big Eight:

  • Milk

  • Soy

  • Eggs

  • Wheat

  • Fish (bass, flounder, cod)

  • Crustacean shellfish (crab, lobster, shrimp)

  • Peanuts

  • Tree nuts (walnuts, pecans)

Prevention of Allergic Reactions

Allergic reactions cause up to 200,000 emergency room visits yearly, and 15 million Americans have some kind of food allergy. Every employee in your facility should be aware of allergens and actively work to keep guests safe from all reactions to food sensitivities, from things like gluten intolerance to severe allergies.

Food Labels

Food labels are required by federal law to include any mention of a Big Eight ingredient. Note the common name of the food, the ingredients list, and if the label includes a “contains” statement.

Staff Actions

When serving an allergic guest, servers should: thoroughly describe dishes, identify ingredients, suggest items that don’t contain the allergen, specify the allergen special order to the kitchen staff, and hand deliver the dish to the guest. Kitchen staff should avoid using the allergen ingredient and avoid passing it to other ingredients or surfaces (cross-contact).


Cross-contact occurs when allergens are passed to food or food contact surfaces, such as: frying shrimp and using the same oil to fry chicken, using the same tools or utensils to handle different foods, or using the same rack to cool peanut butter cookies as oatmeal cookies. Always use separate utensils, pans, cooking oil, gloves, surfaces, etc. Confirm recipes for the presence of allergens and treat them as you would pathogens. Label foods with allergen warnings.

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