How to Prevent Cross Contamination: Allergies, Food Safety, and More

With Thanksgiving around the corner, you’re probably hunting down your favorite recipes and planning your celebratory meal. 

But food safety is an often-forgotten and absolutely crucial component of not only Thanksgiving meals but every meal! 

Concerns about food safety—like how to prevent cross contamination, ensure proper internal meat temperatures, and follow refrigeration and storage guidelines—are key to keeping you and your family healthy this holiday season.

Cross Contamination vs. Cross Contact

Cross-contamination is when harmful bacteria, allergens, or other microorganisms transfer from one substance (like food) or object (like a cutting board) to another. 

However, as of 2013, the FDA (Food and Drug Administration) added the term “cross-contact” to apply to food allergen-related cross-contamination. 

Now, cross-contamination is a general term for food contamination from unsanitary objects (including bacteria, raw food, people, or food-contact surfaces), while cross-contact is more specific to food allergen contamination or the unintentional incorporation of a food allergen into a food.

As microorganisms are microscopic, we cannot see them with the naked eye. Similarly, even tiny traces of a food allergen can trigger serious or life-threatening reactions in people with allergies.

Not taking steps to prevent cross-contact or cross-contamination can lead to food allergy attacks (also known as anaphylaxis) or reactions, as well as foodborne illnesses. 

These are not minor issues—each year in the U.S., foodborne illnesses cause an estimated 128,000 hospitalizations and 3,000 deaths, and 3.4 million people visit emergency rooms for food allergy-related reactions.

Common examples of cross-contamination and cross-contact in a home kitchen include:

• Bacteria from raw meat or food allergens on cutting boards, utensils, or hands getting transferred to another surface or food
• Shared utensils between bacteria-containing food (e.g., using the same tongs to pick up raw chicken and serve cooked chicken) or allergen-containing foods (e.g., using the same knife to spread jelly as you did peanut butter)
• Handling raw meat and then touching other foods or surfaces without washing hands can transfer bacteria
• Washing meat in the sink (it’s not necessary and can get foodborne bacteria on other foods, dishes, or inside the sink) 

How to Prevent Cross Contamination of Allergens

Food protein must be removed from surfaces or utensils with soap and hot water—wiping away crumbs will not be sufficient.

The best way to keep food allergens away from an allergic person is to use separate cutting boards, plates, knives, and other utensils that are solely used for allergy-free foods and store them in a separate area. If possible, it’s best to have separate equipment designed for allergy-free cooking, such as separate toasters, blenders, or baking pans.

If that’s not feasible, you must use utensils, pans, and cutting boards that have been thoroughly washed with soap and water.

Cook the allergen-free meal first, then keep it covered and far away from the allergen-containing meal. If you are cooking foods on a grill, flattop, or fryer, you cannot use the same piece of equipment if allergenic foods have been cooked using it.

If you are handling allergenic food, ensure you wash your hands with soap and warm water before handling the allergen-free meal.

According to Food Allergy Research & Education, both bar and liquid soap are effective at removing food allergens from your hands, but alcohol-based sanitizer is not.

How to Prevent Cross Contamination of Foodborne Bacteria

Most of the tips to prevent cross-contact with allergens also apply to preventing cross-contamination of foodborne bacteria. 

First, washing your hands frequently with warm water and soap before and after handling raw foods (like meat, poultry, eggs, and seafood) is crucial. After you handle or prepare raw meat or proteins, wash your hands, knives, utensils, and surfaces with hot, soapy water or disinfect surfaces with a sanitizing cleaner.

It’s also important to separate cutting boards and utensils. Have one cutting board for raw meats and seafood and another that you only use for fruits, vegetables, or other ready-to-eat foods. Even if you think you washed a cutting board well after dicing raw chicken on it, there may still be foodborne pathogens in the cutting board. 

Never place cooked food back onto a plate that once held raw meat, poultry, seafood, or eggs. Similarly, use different tongs or utensils for serving cooked food than you used to handle the raw protein.

When storing raw meat, poultry, or seafood, keep it in sealed containers or bags on the bottom shelf of the refrigerator. If the bag or package leaks, this ensures that bacteria won’t drip onto other foods below it.

Lastly, never wash raw meat or poultry. Not only is it not necessary, but bacteria can splash in the sink and surrounding areas when you wash raw chicken in the sink.

In addition to preventing cross-contamination, some other food safety tips reduce your risk of getting food poisoning. 

Food Safety Tips for Thanksgiving

According to the U.S. Department of Health & Human Services, there are four main steps of food safety education to remember:

1. Clean

Clean your hands frequently and correctly—that means with soap and warm water for at least 20 seconds. Don’t forget to wash the backs of your hands, between your fingers, and underneath your fingernails, then dry your hands with a clean towel or paper towel. 

You must wash your hands before, during, and after preparing food. Essentially, wash them between each step of cooking—especially if you are handling raw meat or proteins. Don’t wash your chicken or proteins, but make sure to wash fresh foods like fruits and vegetables.

Cleaning your cooking surfaces and utensils is also important to minimize foodborne pathogens, as mentioned in the previous section.

2. Separate

This step is all about preventing cross-contamination, which we discussed in the previous section, including using separate cutting boards, surfaces, and utensils for raw versus cooked or fresh foods.

Additionally, you’ll want to separate raw meat and other proteins from fresh or ready-to-eat foods in your shopping cart. You don’t ever want raw meat, poultry, or seafood packages to touch ready-to-eat foods, fresh produce, or cooked foods. 

3. Cook

During Thanksgiving—and throughout the entire year—it’s crucial to pay attention to the internal temperatures of the meat you are preparing. 

There are different internal temperatures depending on the type of meat and how much heat it takes to kill off the bacteria that are likely to be present in it. 

According to FoodSafety.Gov, here are the internal temperatures you must achieve before serving meat and other commonly cooked proteins: 

• Chicken and turkey: 165°F
• Beef: 145°F
• Ground meat and sausage: 160°F
• Casseroles: 165°F
• Egg dishes (like quiche): 160°F
• Ham (from raw): 145°F 
• Ham (from pre-cooked then reheated): 165°F
• Leftovers: 165°F
• Pork: 145°F
• Fish: 145°F

This is something you can only determine correctly with a meat thermometer. Place the food thermometer in the thickest part of the food, making sure not to touch bone, fat, or gristle.

A common food safety mishap on Thanksgiving is not keeping food at the correct temperature. As holiday meals can be hectic and you often run out of oven space, many dishes frequently get left on the counter for too long. 

If you’re not serving the food right after cooking, ensure it does not enter the “danger zone”—a temperature range between 40°F and 140°F in which foodborne bacteria can grow rapidly. To prevent this, use warming trays, slow cookers, or other hot-holding equipment.

When cooking, be sure to never thaw or marinate foods on the counter—always do so in the refrigerator. 

4. Chill

Another necessary precaution for keeping food out of the danger zone is chilling or storing it correctly.

You’ll need to refrigerate perishable foods within two hours—or one hour if they are exposed to temperatures above 90°F, like in the sun or a hot car. 

We know that after cooking all day and eating a large meal, the last thing you want to do is go back into the kitchen. Still, leftovers must be put into shallow containers (huge containers of hot food often mean bacteria can grow in the middle because they can’t reach chilled temperatures fast enough) and refrigerated promptly.

There are different time periods for each type of leftover food, which can be found in detail on FoodSafety.Gov. Most leftovers need to be consumed within 3 to 4 days. 

After properly chilling your leftovers, it’s time for you to chill!

How to Prevent Cross Contamination FAQs