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Food Safety Part 3: Pathogens and Allergens

People often interchange the terms “cross-contamination” and “cross-contact.” They are very different. Cross-contamination affects the transfer of food pathogens (such as bacteria, viruses, or fungi), whereas cross-contact refers to the transfer of food allergens. Allergens only affect people who have sensitivities to them, whereas anyone can get sick if they eat food that has been contaminated with a pathogen. Understanding the steps for preventing both cross-contamination and cross-contact is useful for people who handle food in child care centers. Food service employees should know the major food allergens and also how to respond to an allergic reaction. This lesson will give you the background needed to differentiate between pathogens and allergens and how to reduce the risk of illness in your facility.

Objectives
  • Name two pathogens that cause foodborne illness and list measures that can be taken to minimize the risk of foodborne illness.
  • Describe how to prevent cross-contamination during food preparation and food storage.
  • Differentiate between food intolerance and food allergy.
  • List three best practices for preventing cross-contact during food preparation.
  • Explain how children with food allergies can be accommodated in the child care environment.

Learn

Know

Food Pathogens

Food pathogens are microorganisms like bacteria, viruses, and to a lesser extent, fungi, that cause disease when ingested. When someone eats a food contaminated with a pathogen, they become sick. This is known as foodborne illness. According to FoodSafety.gov, the top foodborne-illness-causing pathogens that require hospitalization in the U.S. are:

  • Salmonella
  • Norovirus (Norwalk virus)
  • Campylobacter
  • E. coli
  • Listeria
  • Clostridium perfringens

A summary of each of these pathogens, their common food sources, and how to minimize the risk of contamination for them is presented in the following table:

Pathogen

Food Sources

Minimizing Risk

Salmonella

Any raw food of animal origin (e.g., meat, poultry, milk and dairy products, eggs, seafood) and some fruits and vegetables may carry salmonella bacteria. The bacteria can survive to cause illness if meat, poultry, and egg products are not cooked to a safe minimum internal temperature, or if fruits and vegetables are not thoroughly washed. Salmonella can also contaminate other food that comes in contact with raw meat and poultry. 

Safe food handling practices are necessary to prevent bacteria on raw food from causing illness. This includes proper, frequent handwashing; avoiding cross-contamination with other foods during all parts of the food-preparation process; and cooking foods to a safe minimum internal temperature.

Norovirus

Any food served raw or handled after being cooked can become contaminated with norovirus. Other sources include contaminated foods, such as oysters, fruits, or vegetables that may have already been contaminated during production.

Norovirus is the leading cause of foodborne illness in the U.S. Most outbreaks occur in food service settings; food handlers are often the source of the outbreaks. Safe food handling practices (e.g., frequent handwashing using proper techniques, wearing clean disposable gloves when handling food, and changing gloves often) can minimize most risk of norovirus transmission. Also, making sure to properly wash fresh fruits and vegetables and cooking other foods to a safe minimum internal temperature can help reduce the incidence of norovirus.

Campylobacter

Meat and poultry can contain campylobacter. The bacteria can be found in almost all raw poultry because it lives in the intestinal track of healthy birds.

Campylobacter bacteria are extremely fragile and are easily destroyed by cooking to a safe minimum internal temperature. Freezing cannot be relied on to destroy the bacteria.

E. coli

Contaminated foods (e.g. undercooked ground beef, unpasteurized milk and juice, soft cheeses made from unpasteurized milk, and raw fruits and vegetables), untreated water, and any foods handled with unclean hands can be sources of E. coli.

Wash hands often, especially after changing diapers or any contact with animals. Wash hands before preparing or touching food. Cook foods to a safe minimum internal temperature. Avoid eating high-risk foods that are sources of potential E. coli contamination.

Listeria

Foods that are sources of potential Listeria contamination include ready-to-eat deli meats and hot dogs, refrigerated meat spreads, unpasteurized (raw) milk and dairy products, soft cheese made with unpasteurized milk (queso fresco, feta, Brie, Camembert), refrigerated smoked seafood, or raw sprouts. Foods processed in facilities without adequate sanitation practices in place can also harbor Listeria.

The risk of Listeria contamination can be reduced through proper washing of fresh produce, storing raw animal-based food products separately from other foods, washing hands and cleaning and sanitizing food preparation surfaces and equipment after handling uncooked foods, eating perishable and ready-to-eat foods as soon as possible, avoiding consuming unpasteurized dairy products, and heating hot dogs and deli meats prior to consumption.

Clostridium perfringens

Beef, poultry, and gravy—and any mixed dishes made with these foods—are the most common food sources for Clostridium perfringens. Additionally, foods prepared in large batches and held or warmed for a long time before serving can cause Clostridium perfringens infections.

Clostridium perfringens is one of the most common causes of food poisoning in the United States. Cooking kills growing Clostridium perfringens cells that cause food poisoning, but not necessarily the spores that can grow into new cells. If cooked food is not promptly served or refrigerated, the spores can grow and produce new cells. Thoroughly cooking food and keeping food out of the temperature danger zone minimizes the risk of contamination.

Sources: USDA Food Safety & Inspection Service, Centers for Disease Control & Prevention, and FoodSafety.gov.

Factors that Affect Bacterial Growth

As mentioned in Lesson Six, there are six factors that affect bacterial growth on food. These include food, acidity, time, temperature, oxygen, and moisture. This is sometimes referred to by the acronym “FAT TOM.” Some foods are more prone to bacterial contamination due to their characteristics. These include foods like meat, poultry, and seafood products; dairy products like milk and cheese; fresh produce like fruits and vegetables; soy products like tofu; and flavored oil immersions. Cooking destroys many of these bacteria, but not all food is cooked prior to serving. When preparing these foods, the food handler should always take proper precautions to avoid transferring the bacteria from these foods to other foods that will be served ready-to-eat or that are already fully cooked.

Preventing Cross-Contamination

During Storage

Cross-contamination occurs when pathogens in one food are transferred to another food, either directly or indirectly through contaminated surfaces. This transfer can happen at many different points in the food preparation process. While it is always best to strive to keep contaminated food out of the kitchen to begin with, it’s not always possible to do this. Thus, safe food-handling practices become essential to minimizing the transfer of pathogens from contaminated (or potentially contaminated) foods.

Storage is one place where cross-contamination can occur. Proper storage practices include storing food in designated areas only and not with nonfood items, including chemicals. All food (and nonfood) items should be stored at least 6 inches off the floor and away from walls and ceilings. Food should be stored in wrapped or closed containers to prevent contaminants from getting in. Do not reuse nonfood containers to store leftover food; instead, food should only be stored in equipment designated for food.

If your facility has the space and equipment, it is ideal to store raw or uncooked food separately from ready-to-eat food in the refrigerator. If not, though, the recommended storage practice is as follows:

  • Top shelf (ready-to-eat foods): milk, fresh produce, cheese, salads, yogurt
  • 2nd shelf (cook to 140 F): reheated foods (precooked), such as ham or breaded chicken
  • 3rd shelf (cook to 145 F): fresh beef (not ground beef) or pork, seafood
  • 4th shelf (cook to 160 F): ground beef or pork, eggs
  • Bottom shelf (cook to 165 F): raw chicken or turkey (including ground), leftovers, casseroles

During Preparation

Another opportunity for cross-contamination to occur is during food preparation. Doing things like properly washing hands, washing hands often, and wearing and changing disposable gloves can prevent the transfer of pathogens. Make sure the food prep area, including surfaces and equipment, are thoroughly cleaned and sanitized. Another good practice is to prepare raw or uncooked meat, poultry, and seafood at a different time than ready-to-eat foods, and then clean and sanitize the surfaces and equipment when you are done. Never allow ready-to-eat foods to touch surfaces that have come into contact with raw or uncooked meat, poultry, or seafood.

Not all foods that are at risk for harboring pathogens are meats. Fresh fruits and vegetables can also carry pathogens from growing conditions or handling before they arrive at your facility. Thoroughly wash all fresh produce under warm, running water to remove any dirt or residue. Foods like lettuce and spinach should have each leaf washed separately. Remember to scrub the peels or rinds of fruits and vegetables before cutting them, because if there are pathogens on the outside of the food, cutting them will transfer the pathogens inside as the food is cut. Once fresh produce has been prepped, it needs to be stored, wrapped and labeled in the refrigerator until served. Use the Preventing Contamination During Food Preparation Fact Sheet below from the National Food Safety Management Institute and make this resource available to all food service staff at your facility.

color-coded cutting boards help prevent food contamination

Cross-Contamination from Chemicals

The chemicals used to clean and sanitize the kitchen can be another source of contamination. Although this type of contamination is not from pathogens, it can still make people sick. Chemicals used in food service should be stored in their own area, away from food and nonfood-related supplies and equipment. Chemicals should be stored in proper containers, which are those labeled with the information about the chemical. Do not reuse old food containers to store chemicals.

Towels used for cleaning and sanitizing should be kept in their respective pails when not in use. Towels used to clean food spills should not be used for any other purpose; doing so can cause cross-contamination. Make sure that all cleaning agents and sanitizing solutions are used in the proper concentrations and that residues are rinsed or wiped clean.

Food Allergens

Food Allergies vs. Food Intolerances—What’s the Difference?

Many people get food allergies confused with food intolerances. While both conditions can cause adverse symptoms as a result from exposure to a trigger food, food intolerances only involve the digestive system and do not involve an immunological response from the body. Common food intolerances include gluten, milk and dairy, and monosodium glutamate. Although food intolerances do not cause life-threatening symptoms, they can still be very uncomfortable for the food-intolerant child, and considerations should be made when menu planning.

Food allergies, on the other hand, occur when certain foods are ingested, triggering an immune response by the body. When a person with a food allergy is exposed to the trigger food, their body starts producing a specific antibody, called immunoglobulin E, that binds to a protein in the food that is responsible for the allergy. This, in turn, causes allergic symptoms such as hives, rashes, and restricted breathing.

Children may not be good at articulating their symptoms, especially young children. A child experiencing symptoms from an allergic response to a food might say things like:

  • My throat is itchy/scratchy/puffy/feels tight
  • My tongue is hot/itchy/tingly
  • There’s something stuck in my throat
  • My mouth feels funny
  • This food is spicy (especially when not eating a spicy food)

Symptoms of an allergic response can be mild or severe. Mild symptoms can include hives or rash, nausea or vomiting, stomach pain, nasal congestion, or a runny nose. Severe allergic response includes symptoms like swollen or puffy lips, tongue, or throat; shortness of breath; tightness in the chest; dizziness; rapid heartbeat; a drop in blood pressure; or anaphylaxis. Severe allergic symptoms need to be addressed right away, as death can occur if not treated promptly. If a child exhibits symptoms of anaphylaxis, he or she will require immediate medical treatment, including an epinephrine injection and a trip to the emergency room. Check your center’s policy for storage, administration, and training related to epinephrine medications. An allergic child should have a designated person to administer emergency medication in her or his food allergy action plan on file at the center.

While the supervision of children during mealtimes is primarily the responsibility of direct care staff, it is important for all program staff to be aware of the signs of an allergic reaction and the necessary steps for addressing the situation.  Check with your program’s specific protocols for handling food allergies.

The 8 Major Food Allergens

The proteins of specific kinds of foods are responsible for food allergies. While there are more than 160 types of foods that can cause an allergic response in sensitive individuals, these eight foods account for 90 percent of food allergy reactions:

  1. Milk
  2. Eggs
  3. Fish
  4. Crustacean shellfish (e.g. crab, lobster, shrimp)
  5. Tree nuts (e.g., almonds, walnuts, pecans)
  6. Peanuts
  7. Wheat
  8. Soybeans

These foods—and any food containing them—by law must be identified on the food product’s label. The allergen can be identified in the ingredients list, or at the end of the ingredients list, with a statement such as “Contains wheat, soy, and milk ingredients.” Some companies may also opt to use precautionary labeling, in which they voluntarily disclose when a food product that does not contain any of the eight major food allergens is produced in a facility where these allergens are also processed. An example of a statement might read, “Processed in a facility that also processes peanuts and tree nuts.” Precautionary labeling is not required by law and can vary widely in its use. Make sure to check the labels of all food products for the presence of allergens during the receiving process. When you serve the food, a recommended practice is to keep the labels of all foods prepared for 24 hours in the event a child suffers an allergic reaction. You might even consider keeping a “label library,” where you retain all actual food labels (or scan them and save them electronically).

Avoiding Cross-Contact

Child care centers are responsible for promoting a safe physical environment that protects children with food allergies. State and local health regulations outline requirements governing the cleaning and sanitizing of surfaces and other practices that can protect against cross-contact during food preparation. Cross-contact refers to the unintentional transfer of an allergen from a food containing that allergen to a food that does not contain the allergen. It is important to understand that cooking does not reduce or eliminate the chances of a person with a food allergy having a reaction to the food eaten.

Some practices to reduce the incidence of cross-contact include:

  • Clean and sanitize—with soap and water or all-purpose cleaning agents and sanitizers that meet state and local food-safety regulations—all surfaces that come into contact with food in kitchens, classrooms, and other locations where food is prepared or eaten.
  • Clean and sanitize food preparation equipment, such as food slicers, and utensils before and after use to prevent cross-contact.
  • Clean and sanitize trays and baking sheets after each use. (Oils can seep through wax paper or other liners and cause cross-contact.)
  • Use proper handwashing procedures that emphasize the use of soap and water. Hand sanitizers are not effective in removing food allergens, which are protein-based substances.

Other best practices that food service staff can use to reduce the incidence of cross-contact when preparing food include:

  • Prepare and store allergen-free foods separate from other foods.
  • Label foods with stickers, color coding, or other methods to indicate whether a food is allergen-free.
  • Store allergen-containing foods away from other foods to prevent cross-contact.
  • Prepare allergen-free menu items first. These foods may need to be prepared on a separate, clean pan to avoid cross-contact.
  • Wear a new pair of disposable gloves when preparing and handling allergen-free foods.
  • Thoroughly wash any work surface with detergent solution using a clean towel. Rinse with clean water. Sanitize surface and allow to air dry
  • Change your water and obtain a different cleaning towel before cleaning any other area of the kitchen, serving, or dining area.
  • Be certain that all utensils, knives, cutting boards, or other equipment are cleaned and sanitized before use on next product. Change apron as needed to prevent cross-contact.
  • Familiarize yourself with the children who have food allergies.
  • Train staff and other personnel to recognize symptoms and monitor the area surrounding the child with allergies.
  • Designate an allergy-free area and or table (note that children cannot be required to use these designated allergen-free zones because of privacy laws).
  • Clean all tables and chairs thoroughly with soap and water and sanitize with approved sanitizing agent. Use a dedicated bucket for both cleaning and sanitizing a peanut-free area.

Accommodating Children with Food Allergies in Child Care Centers

The National Food Safety Management Institute identifies four strategies or steps to accommodate children with food allergies.

Step 1: Be aware of the food allergies in your child care center; consider the various allergies as you go about menu planning, reading labels, and following safe food-handling principles. 

Step 2: Know the requirements for serving food to students with special dietary needs. This information is in the USDA guidance, and if your child care center has a food allergy policy, the information would be there, as well.

Step 3: Develop a partnership with open communication and education for all those involved with the child’s care. Parents of students with food allergies have a lot of experience and expertise in the topic, so they can be an asset to the child care center’s team.

Step 4: Implement the directives of a licensed physician, physician assistant, or nurse practitioner. If a child has a form on record with the center that indicates the student has a food-related disability as defined by the Americans with Disabilities Act Amendment Act of 2008, food services is required to make the accommodation. If there is no disability, the accommodation is not required, but can be made as a gesture of support and customer service.

Because food allergies can be severe—and potentially life-threatening—child care providers must be aware of all allergies in the children in their classroom or care group. Proper and accurate documentation and regular communication between parents, child care center directors, classroom staff, and food service personnel can help to keep everyone in the loop about food allergies. For instance, the child care center’s director should discuss allergies with the child’s family when the child is being enrolled. Any information about the child’s allergies, including treatment plans, should be documented in the child’s file. As food service personnel, your responsibility is to know which allergies, restrictions, and preferences are present at your center so that the menu planning process can account for these situations.

Food Allergy Action Plans

The Centers for Disease Control and Prevention published a resource in 2013 called Voluntary Guidelines for Managing Food Allergies in Schools and Early Care and Education Programs. This is a comprehensive resource for food service personnel when it comes to procedures for addressing food allergies. One outcome of the CDC’s work was the recommendation for each facility to develop a food allergy management plan with these five priority areas:

  1. Ensure the daily management of food allergies in individual children.
  2. Prepare for food allergy emergencies.
  3. Provide professional development on food allergies for staff members.
  4. Educate children and family members about food allergies.
  5. Create and maintain a healthy and safe educational environment.

Does your center have an allergy plan? If so, are any of these five areas in your plan? Make the following resource, CDC Voluntary Guidelines for Managing Food Allergies in Schools and Early Care and Education Programs available for use at your facility.

See

How do Department of Defense child care centers handle food allergies? What are some of the steps involved in documenting and tracking food allergies? What are some of the processes used when preparing food for food-allergic children? How is cross-contact minimized? Watch these video clips, in which a registered dietitian (or food service director) explains best practices to track and manage food allergies in child care kitchens.

Allergens

Watch this video to learn how to best manage and track food allergies in your child care kitchen.

Do

How much do you know about preventing foodborne illness from unsafe food handling in your facility? Use the Foodborne Illness Self-Assessment Tool below to determine your facility’s risk. Answer each item on the survey. If you do not know an answer, check with your supervisor. Later, discuss with your supervisor how you can adapt your practices to better prevent foodborne illness.

Explore

In the following video, a food service employee goes about the food preparation process for making lunch. Write down each point where cross-contamination could occur. Make a note of instances when the employee does something right to minimize the occurrence of cross-contamination.

Cross Contamination

Look for potential points of cross-contamination and quality practices to minimize contamination.

Apply

Two key skills of food service workers in child care centers is to know how to address food allergies and how to respond when a child suffers from an allergic reaction. Use the Food Allergens at My Center checklist to see where you may need to make changes. Then, meet with the child care center director and find out what allergies are present at your center. Does each child with an identified allergy have an allergy care plan on file? How does it compare to the Food Allergy Research & Education’s (FARE) Food Allergy & Anaphylaxis Emergency Care Plan (see below)?

What allergies are present at your facility?

Go through the food inventory you have in your kitchen. Check the labels on each package. How many foods did you find that are referred to in allergy care plans on file with the center?

Discuss with your supervisor your center’s protocol for addressing food allergies. If training is required to respond to food allergies, arrange to schedule that training.

Glossary

Anaphylaxis:
a severe, and potentially life-threatening, allergic reaction that involves multiple body systems, such as the respiratory system, digestive system, circulatory system, or skin.
Cross-Contact:
the unintentional transfer of an allergen from a food containing that allergen to a food that does not contain the allergen
Cross-Contamination:
the transfer of a pathogen (such as bacteria, viruses, or fungi) or chemical from a food or surface to another food or surface
Food Allergy:
a reaction to a food that results in an immune response by the body
Foodborne Illness:
sickness caused by ingesting a foodborne pathogen, such as a bacteria, virus, or fungus
Food Intolerance:
when a person has difficulty digesting certain foods and can result in symptoms such as intestinal gas, abdominal pain, or diarrhea; food intolerances involve the digestive system but do not invoke an immune response
Food Pathogen:
microorganisms like bacteria, viruses, and to a lesser extent, fungi, that cause disease when ingested
Food-Related Disability:
the Americans with Disabilities Act Amendments Act of 2008 broadened the definition of disability to include “Major Bodily Functions,” which includes “functions of the immune system, normal cell growth, digestive, bowel, bladder, neurological, brain, respiratory, circulatory, cardiovascular, endocrine, and reproductive functions.” Children who have a medical form signed by a licensed physician stating that the child has a food-related disability that requires a food substitution must be accommodated under this amendment of ADA. If a required meal component is substituted with a non-creditable food to accommodate a child with a food-related disability, that meal remains reimbursable to the child care institution.

Demonstrate

Which of the following is not a best practice for preventing cross-contact during food preparation?
True or false? Food intolerances are the same as food allergies.
What is the difference between "cross-contamination" and "cross-contact"?
References & Resources

American College of Allergy, Asthma, and Immunology. (2014). Retrieved from https://acaai.org/allergies/anaphylaxis

Centers for Disease Control and Prevention. (2013). Voluntary Guidelines for Managing Food Allergies in Schools and Early Care and Education Programs. Washington, DC: US Department of Health and Human Services. https://www.cdc.gov/healthyschools/foodallergies/pdf/20_316712-A_FA_guide_508tag.pdf 

Eller, P. & Skolmowski, J. (n.d.). Food Allergies: Think Smarter, Not Harder. Washington, D.C.: U.S. Department of Agriculture. 

Food Allergy Research & Education. (n.d.). Retrieved from https://www.foodallergy.org/

National Food Service Management Institute. (2014). Managing Food Allergies in School Nutrition Programs online training module.

National Restaurant Association’s ServSafe Course Book, 6th edition. 2014.

University of Mississippi. (2016). Food Safety in Child care: Instructor’s manual.

USDA Food and Nutrition Service. (2017). Accommodating Children with Special Dietary Needs in the School Nutrition Programs. Guidance for School Food Service Staff. Retrieved from https://www.fns.usda.gov/2017-edition-accommodating-children-disabilities-school-meal-programs