How to Reduce Cross-Contamination If You Have Food Allergies

People who are diagnosed with food allergies need to avoid eating the foods that trigger their symptoms. However, simply avoiding those allergenic foods often isn’t enough to eliminate symptoms—that’s where cross-contamination comes in.

Woman scooping mango chunks from a toppings bar at a frozen yogurt place
Raphye Alexius / Getty Images

Cross-contamination occurs when a food allergen contaminates a food that is naturally free of allergens. For example, during food preparation in the kitchen, bread crumbs from a regular slice of toast may be left behind in a toaster. These leftover crumbs in the toaster may then contaminate a wheat-free slice of toast, causing an allergic reaction for someone with celiac disease or non-celiac gluten sensitivity.

This problem also can occur in manufacturing facilities. For example, food products made with tree nuts can contaminate the processing of other foods made on the same manufacturing line. For this reason, products are required to include a warning if their facility also manufactures foods that include one of the top food allergens on the same processing equipment.

Cross-contamination can occur almost anywhere, at home, in restaurants, at school or on manufacturing lines.

Cross-contamination can happen during food preparation, cooking, storage, or even when serving. All it may take is gluten-free pasta cooked in the same pot that was used for regular pasta, eating a salad after a piece of cheese is removed from the top or a knife not properly cleaned from the peanut butter jar. For a person with food allergies, these situations can lead to life-threatening reactions. To help safeguard your food, follow these guidelines to reduce the risk of an allergic reaction.

Cross-Contamination in Packaged Foods

Food manufacturers often use the same facilities or equipment to process and package products that contain allergens. To safeguard yourself:

  • Carefully read the labels of foods, looking for any mention of the food to which you’re allergic.
  • Watch for statements like “processed in a facility that also manufactures wheat” or similar disclosures. These can tell you when there’s a risk that nuts or some of the other most common food allergens may be present.
  • If you are not sure about the information or do not see it on the label, it is always best to contact the company and ask about your concerns over safe practices.

Cross-Contamination in the Home

In most households where family members with food allergies have a high risk of anaphylaxis, family members avoid bringing foods with those allergens into the house. This is the safest way to avoid cross-contamination. If the house is clear of these foods, all family members can live in a safer, allergy-free environment.

If you do however keep foods with these allergens in the home, follow these rules:

  • Keep foods that contain problematic allergens far from common food preparation and serving areas. Foods containing allergens should also only be eaten in certain areas of the kitchen so that any residue does not wind up in other areas of the home.
  • Label everything appropriately. Keep in mind that baby sitters, grandparents or friends need to be able to recognize the dangers of the foods should they be in charge of the food or dining at your house.
  • Designate special food preparation areas and utensils for “allergen-free” use, and clean all food surfaces before and after food preparation.
  • Remember that the riskiest foods for cross-contamination are foods that are messy, difficult to clean, or likely to leave crumbs, oil, or other trace allergens on surfaces. When you’re aware of the possible risks, you can improve the safety of the person with food allergies.

Cross-Contamination in Restaurants

When choosing a restaurant, it is important to determine if the restaurant’s staff members are familiar with food allergies and have an established protocol for food safety. Speak to a manager before ordering to make sure the staff understands your food allergy-related needs.

Still, despite a restaurant’s best efforts, cross-contamination can still occur if all safe practices are not upheld. The most common causes of cross-contamination in restaurants are often related to the frying oil, griddles or grills, and woks. The actual cooking of food poses more risk in a restaurant than in typical prep areas, as those areas are usually more closely monitored and understood.

When dining out:

  • Don’t be afraid to double-check with your server about food preparation to be safe.
  • Consider carrying a “chef card” that lists your allergies and explains how and why the kitchen staff needs to avoid cross-contamination.
  • Keep in mind that it is important to recognize that fried foods are often a source of cross-contamination, as cooking it in the same oil can lead to an allergic reaction.
  • If there is a mistake with your food order that requires you send it back, be sure the server understands you need a brand new meal. Removing the wrong item, like an egg or a piece of cheese that may have touched the rest of the meal, particularly if it is an allergen, is not acceptable, as the meal has been cross-contaminated.
  • Consider avoiding salad bars, buffet-style restaurants, and ice cream parlors. These eateries are rife with potential cross-contamination, since spoons, scoops and serving tongs can be moved from one food (containing an allergen) to another (free from allergens), contaminating it.

A Word From Verywell

There are several other common ways that cross-contamination can occur, and you should be aware of them.

For example, knives, cutting boards, counter surfaces, and spoons are at high risk for cross-contamination, since they’re often used repeatedly with different types of foods. Make sure they’re washed thoroughly with hot soapy water. Plastic cutting boards provide a safer option as they are easier to clean and sanitize than wooden boards as they can also be cleaned in the dishwasher.

Be particularly careful about nuts and seeds, as they may leave an oily residue, potentially leaving allergens behind on plates, counters, tables and cutting boards. Clean with a household cleaning agent thoroughly to prevent cross-contamination.

Refrain from sharing cups or eating utensils with others, as they can easily be contaminated with allergens. For some people, all it takes is a simple touch of the hand, face or lips to evoke an allergic reaction.

Bagel or meat slicers, if not cleaned thoroughly, may be contaminated with food allergens. Be sure to advise at the deli counter that you have a food allergy and ask for them to change their gloves and to clean the machines before slicing.

Bulk food bins may also be a source of cross-contamination as the sharing of scoops between items can potentially transfer allergens. Always ask the store manager if cross-contamination precautions have been taken.

In any case, if you believe there’s a risk of cross-contamination either at home or in another setting, choose a different food or don’t eat.

1 Source
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Food allergies.

By Jill Castle, MS, RD
Jill Castle, MS, RD, is a childhood nutrition expert, published book author, consultant, and public speaker who helps parents nourish healthy kids.