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Cross-Contact and Food Allergies in Infants and Toddlers

If your child has a food allergy, ingredients are not the only thing you need to pay attention to. You also need to be mindful of how foods are made and handled. A food that seems safe could still cause a reaction if it has touched a food containing your child’s allergen. This is called “cross-contact.” While this can feel overwhelming, there is good news. Once you understand how cross-contact happens and where it is most likely to occur, there are simple steps you can take to help prevent it.

In this section, you will learn how to:

  • Understand what cross-contact is and why it matters
  • Recognize the most common ways it happens
  • Take simple steps to avoid cross-contact in your home
  • Reduce the risk when your child eats outside your home
  • Prepare questions for your child’s doctor about cross-contact
A woman holding a baby smiles while helping a young girl follow a recipe in a bright kitchen. Baking ingredients and utensils are spread on the counter in front of them.
  • alert iconThis guide is here to support you with easy-to-understand, medically reviewed food allergy and anaphylaxis information you can trust. Use this as a resource as you prepare to talk with your child’s healthcare team.

What is cross-contact and how does it happen?

Cross-contact happens when a food allergen gets onto a food that is supposed to be safe and allergen-free. The part of food that causes allergic reactions (called proteins) can be so small that you cannot see it. Your child’s immune system can notice even tiny amounts of these proteins and start an allergic reaction. Cross-contact usually doesn’t happen because someone is careless. It often happens because people don’t realize what to watch for when cooking, serving, eating, or cleaning up after a meal.

There are three main ways cross-contact can happen:

1. Food-to-Food Contact

Food-to-food contact happens when an allergen touches another food. This can occur during storage, cooking, plating, or serving.

It may happen directly when two foods come into contact, such as foods touching on the same plate or sharing a container. It can also happen indirectly, when allergen proteins get onto utensils, plates, or pans that are then used to prepare a food that is supposed to be safe.

Large spills or crumbs are easier to notice, but small amounts of allergens can spread to other foods or surfaces without anyone realizing it. Common ways this can happen include:

  • Steam or splatter from cooking on the stove landing on nearby foods.
  • Small crumbs being left behind in dips or spreads such as butter, jelly, or cream cheese.
  • Using the same knife, spoon, tongs, or other utensil for multiple foods without washing it in between.

It is important to know that once foods have touched, removing the visible allergen does not make the food safe. For example, if a slice of cheese is placed on a burger and then taken off, it may remove what you can see, but tiny amounts of dairy protein can still be on the burger and cause an allergic reaction.

2. Surfaces and Objects

Allergens can get left behind on surfaces and objects after food touches them. When your little one grabs that surface, the allergen can end up on their hands and sometimes into their mouth. Children may also put toys or surfaces directly into their mouths. This is especially common for babies and toddlers, who love to taste-test everything they see and cannot wash their hands like adults can.

3. Saliva

After eating, small amounts of allergen protein can stay in the saliva for a while. These proteins can be passed to your child if they share cups, utensils, or pacifiers with others, or if they receive kisses on or near the mouth. Pets can also spread allergens if they have recently eaten a food containing your child’s allergen and then lick your child or their toys.

To lower the risk, avoid sharing cups, utensils, or saliva (such as kissing near the mouth) for a few hours after eating a food containing your child’s allergen. Brushing teeth and eating an allergen-free meal may help lower the amount of allergen in the mouth, but they do not get rid of it completely.  

Note: You may also hear the word cross-contamination. This sounds similar but actually means something different:

  • Cross-contact: Allergen protein from one food gets on another food. This may cause an allergic reaction.
  • Cross-contamination: Bacteria or germs from one food get on another food. This may cause food poisoning.

For families managing food allergies, cross-contact is the main concern, so knowing how it happens and how to prevent it is key.

What you can do to avoid cross-contact

You might be wondering, “How can I possibly control something that I can’t even see?” That’s a great question. Fortunately, there are many small steps you can add to your daily routine to lower the risk of cross-contact.

The main ways to prevent cross-contact are keeping safe and unsafe foods from touching and cleaning surfaces, tools, and hands well. Here are some of the ways that you can prevent cross-contact:

  • Check ingredient lists to make sure that the allergen isn’t present before preparing food.
  • Companies can change the ingredients in their products without notice, so check labels every time.
  • If you are unsure about a food, don’t serve it until you can confirm it’s safe.

(See our How to Read Food Labels page for more.)

Keeping safe foods away from allergen-containing foods makes it less likely that proteins will get onto the packaging or into the food. It also helps prevent mistakes, especially when others are helping, like babysitters or visiting relatives. Some tips to help with this:

  • Keep allergen-free foods together in their own section of the shopping cart while at the store.
  • Consider having a shelf, bin, or cabinet at home that is only used for safe foods.
  • Keep safe foods in sealed containers to protect them from crumbs or dust from nearby allergen-containing foods.

Soap and water are the best way to remove allergens from hands. Hand sanitizer does not fully get rid of allergen proteins.

Wash hands before preparing any food, after handling allergen-containing foods, and before serving your child.

  • Wash for at least 20 seconds, scrubbing between fingers and under nails.
  • Use a clean towel or disposable paper towel to dry hands—dirty towels can transfer proteins back onto hands.

Regularly wiping down areas where food is made or eaten, as well as surfaces that are often touched, can help lower the chance of allergens getting onto your child’s hands or food. Soap and water or wet wipes both work well.

Common high-touch surfaces include highchairs, tables, and toys. For babies who are crawling, it is also helpful to frequently clean floors in areas where food is made or eaten.

Allergen proteins are often too small to see, so how do you know when you’ve cleaned a surface well enough?

  • Use soap and warm water to wipe down the entire surface, not just the areas that look dirty.
  • Wash surfaces the same way you would wash a dish: scrub, rinse, and dry with a clean towel or paper towel.
  • Clean the area until you can’t see any crumbs, oily spots, or sticky areas left.

Soap and water or sanitizing cleaners and wipes (for example, Clorox or Lysol) are the best options for getting rid of allergens on surfaces.

Before preparing allergen-free food, make sure to:

  • Wash countertops and cutting boards
  • Use a clean cloth or fresh sponge (allergens can get trapped in sponges and then spread to other surfaces when used again).
  • Clean highchair trays or any other surface where your child eats.
  • Keep separate cookware and utensils for allergen-free foods if possible—some families use different colored tools to make it easy to tell them apart.
  • If separate cookware isn’t possible, prepare allergen-free food first.
  • Wash all cookware, utensils, and other tools with soap and water between uses.
  • Avoid appliances that are difficult to clean between uses, like toasters.

When you’re preparing multiple dishes, allergens can easily get onto your hands, utensils, and surfaces. To reduce the risk of cross-contact:

  • Cook allergen-free foods first—before any allergen-containing foods are taken out or used.
  • Serve your child’s food before other dishes.
  • After serving, try to avoid passing shared dishes around the table, since crumbs or tiny amounts of allergens can land on your child’s plate.

It is also important to know that cooking does not remove allergens from food or prevent allergic reactions. For example, heating a dish does not remove allergen proteins the way it can kill some bacteria that cause foodborne illness.

Food allergens are not only found in what your child eats. Some craft supplies, soaps, lotions, and cosmetics can contain ingredients like milk, wheat or nuts. For example, Play-Doh often has wheat. Some lotions may contain nut oils.

Always read product labels and ask about ingredients before letting your child use these products.

Cross-contact outside the home

You’ve learned how to prevent cross-contact in your kitchen, but what about when your child eats meals outside your home or made by someone else? A simple way to stay prepared is to keep a ‘to-go kit’ with wipes, safe snacks, and emergency medicine whenever you leave the house. Here are some common situations to consider and tips for handling them.

Daycare and school environments can be stressful when your child has a food allergy. Kids share spaces, surfaces, and sometimes snacks, and you have to rely on others to prevent allergen contact. Many schools and daycares have policies for managing food allergies, but these policies can vary. Talk with your child’s teachers, aides, nurses, and administrators early on about your child’s food allergies. This helps them understand your child’s needs and makes sure everyone knows how to follow the Anaphylaxis Action Plan. Keep in touch with them regularly so you can review any updates to your child’s allergy management.

Here are some things to consider or questions that you may want to ask your child’s school:

  • Ask if an allergen-free table or special area is available for children with food allergies.
  • Ask how shared foods or special classroom events (like birthday treats or parties) are handled.
  • Find out where epinephrine is kept and which staff members are trained to use it.

Social gatherings can be tricky for families managing food allergies. You may not know how foods were made, whether allergens are present, or how careful others will be about cross-contact. It can be especially difficult to explain why avoiding cross-contact is so important if a host isn’t familiar with food allergies or doesn’t fully understand the risks. Sometimes hosts may not be able to follow all safety requests, so having backup strategies and planning ahead is important. You can help keep your child safe and reduce stress by communicating with the host early, offering solutions, and deciding in advance how you will handle potential challenges.

Tips for attending parties and events:

  • Before the event – Tell the host about your child’s allergies and ask what foods or snacks will be served. Ask if allergen-free options can be prepared first and kept separate.
  • Offer support – Offer to help plan the menu or bring safe foods everyone can share. Ask the host to keep food labels so you can review ingredients. Remind family and friends not to share food, utensils, or drinks with your child.
  • Plan ahead – Bring safe foods and snacks so your child always has something to eat. Bring wipes to clean eating areas. Pack emergency epinephrine and stay nearby to keep an eye on your child while they eat.

Eating at restaurants can be challenging because many ingredients and cooking tools are used in the same kitchen. Here are some tips for dining out safely:

  • Look at the menu online before you go.
  • Call ahead to ask if the restaurant can accommodate your child’s food allergies.
  • Bring a chef card listing your child’s allergens and give it to the server.
  • Remind staff about the allergy when you are seated and explain that even tiny amounts can cause a reaction.
  • Ask if separate utensils, cooking surfaces, or preparation areas are used in the kitchen.
  • Wipe down tables, highchairs, menus, salt and pepper shakers, and any other item your child could touch with their hands or put in their mouths.
  • If you do not feel comfortable or feel that the allergy is not being taken seriously, it is okay to leave.

These settings carry a higher risk of cross-contact since many foods are prepared or served in the same shared space. Serving utensils can sometimes be swapped or used for the wrong food. Because of this, it’s often safest to avoid these settings when possible. If you do need to order from a deli counter or buffet:

  • Inform staff about your child’s food allergy.
  • Ask for clean gloves and clean tools.
  • Request freshly opened packages when available.

Preparing and cutting up different foods with a knife on a single cutting board.

Building an allergy-smart household

An allergy-smart home setup makes everyday life easier and helps everyone feel good while going about their daily lives. These ideas can help you turn your house into an allergy-smart one to lower the chance of cross-contact.

Deciding whether to keep allergens at home

Some families choose to keep foods that contain allergens in the house. Others decide it is safer not to have them at all. There is no one right answer! It depends on your family’s needs, and you and your family can figure it out together. What you decide depends on:

  • How severe your child’s reactions have been in the past.
  • Whether the allergen is easy or hard to clean up.
  • How mature your child is and whether they can understand the rules about allergens.
  • The size and layout of your kitchen and eating spaces.
  • Whether you have a plan to store and prepare foods separately.
  • What feels manageable and safe for your family.

If you’re unsure, talk with your child’s healthcare team to determine what is best for your family.

Keeping allergens in the house

If you choose to keep your child’s food allergens in the house, having a clear routine helps lower the chance of cross-contact.

  • Have set spaces for safe food and foods that contain your baby’s allergens. Store allergenic foods in sealed containers and on separate shelves away from safe foods.
  • Use separate or clearly marked utensils, plates, pots, and cutting boards for allergen-free meals. Multi-colored cooking supplies can help everyone remember which tools are safe.
  • If you don’t have extra sets, cook allergen-free foods first. Wash all tools with soap and water or use the dishwasher before preparing other foods.
  • Wipe counters, tables, and highchairs with soap and water after meals where allergens are served.
  • Wash your hands with soap and water after eating or touching allergenic foods. Hand sanitizer does not remove allergens.

Create an allergen zone in your kitchen

Set up your kitchen with clear spaces makes preparing meals safer and more organized.

  • Choose a part of the kitchen as your “allergen zone.” Use it only for foods containing allergens. This can be a dedicated cutting board or surface that can be easily washed. 
  • Store safe foods, tools, and dishes in one separate area to avoid mix-ups.
  • Label shelves and storage bins so everyone knows what belongs there.
  • Teach family members and babysitters how to use the allergen-safe area and why it matters.

Top 9 allergens cause 90% of food allergy reactions

Certain foods are much more likely to cause food allergies in infants and toddlers. Here are the top 9 food allergens that cause the most reactions:

Allergen

Alternative Names

Latin / Botanical Name(s)

Milk

  • Casein
  • Whey
  • Lactose
  • Butter fat
  • Ghee
  • Curds
  • Cheese powder
  • Yogurt extract
  • Milk peptide complex
  • Lactis
  • Lactalbumin
  • Lactoglobulin
  • Caseinum

Egg

  • Albumin
  • Ovalbumin
  • Globulin
  • Livetin
  • Silici albuminate
  • Egg solids
  • Egg powder
  • Ovum protein
  • Lysozyme
  • Ovum
  • Albumen
  • Ovalbumin

Peanut

  • Arachis oil
  • Groundnut
  • Beer nuts
  • Artificial nuts
  • Nut pieces
  • Peanut butter
  • Arachis hypogaea

Tree Nuts

  • Almond: marzipan, praline, almond paste
  • Cashew: Anacardium occidentale
  • Walnut: Juglans regia
  • Hazelnut: filbert
  • Pecan, Brazil nut, Pistachio, Macadamia

Look for terms like nut butters, nut oils, or mixed nuts
  • Prunus amygdalus dulcis (Almond)
  • Juglans regia (Walnut)
  • Carya illinoinensis (Pecan)
  • Anacardium occidentale (Cashew)
  • Corylus avellana (Hazelnut)
  • Bertholletia excelsa (Brazil nut)
  • Pistacia vera (Pistachio)
  • Macadamia ternifolia (Macadamia nut)

Soy

  • Edamame
  • Soy lecithin
  • Soy protein isolate or concentrate
  • Textured vegetable protein (TVP)
  • Miso
  • Natto
  • Tempeh
  • Tamari
  • Shoyu
  • Tofu
  • Soya
  • Phytoestrogens
  • Soy sterols
  • Hydrolyzed soy protein
  • Glycine max

Wheat

  • Durum
  • Semolina
  • Spelt
  • Farina
  • Graham flour
  • Enriched flour
  • Bulgur
  • Kamut
  • Hydrolyzed wheat protein
  • Modified food starch (if from wheat)
  • Wheat amino acids
  • Triticum vulgare (wheat germ oil)

Fish

Common examples:
  • Marine collagen
  • Bass
  • Cod
  • Flounder
  • Haddock
  • Salmon
  • Tilapia
  • Watch for: fish stock, fish sauce, anchovy paste, imitation seafood
Tuna:
  • Albacore (Thunnus alalunga)
  • Bigeye tuna (Thunnus obesus)
  • Bluefin tuna (Atlantic: Thunnus thynnus; Pacific: Thunnus orientalis)
  • Skipjack (Katsuwonus pelamis) – often used in canned "light tuna"
  • Yellowfin tuna (Thunnus albacares) – often sold as “ahi”
  • Bonito
Fish are often labelled by species or source. Some Latin names include:
  • Gadus morhua (Cod)
  • Salmo salar (Atlantic salmon)
  • Fish derivatives may also appear as: Piscum (general Latin root for fish)

Shellfish

  • Shrimp
  • Crab
  • Lobster
  • Prawns
  • Crawfish
  • Mollusks (clams, mussels, scallops, oysters)
  • May appear as: shellfish extract, seafood flavoring
  • Chitosan
Shellfish Latin names vary widely by species:
  • Penaeus spp. (Shrimp)
  • Homarus americanus (Lobster)
  • Callinectes sapidus (Blue crab)
  • Crassostrea virginica (Oyster)
  • Mytilus edulis (Mussel)
  • Mollusks (clams, mussels, scallops, oysters)
  • Pecten maximus (Scallop)

Sesame

  • Tahini
  • Benne
  • Gingelly
  • Sim sim
  • Sesamol
  • Sesame paste
  • Sesame oil
  • Halvah
  • Sesame seeds or flour (may be hidden in seasoning blends)
  • Sesamum indicum

These foods can cause severe reactions when consumed on their own by a child with food allergies. They can also cause reactions if they come into contact with a safe food your child eats.

Questions & answers (Q&A) on cross-contact and food allergy

Cross-contact usually happens during food prep and can easily be missed. Awareness is key. Over time, with clear rules in place and practice, it will become part of your routine. Here are answers to some common questions we’re asked about cross-contact and food allergies.

Using the same cutting board, knife or utensil for different foods without washing them can cause cross-contact. Even unwashed hands can spread food allergens.

Spreading bread with nut butter and then cutting fruit on the same board can transfer nut protein to the fruit.

Using a knife to spread butter on toast and then dipping that same knife into the jam jar can leave traces of milk protein in the jam. Next time you use the jam you may not remember it has been in contact with an allergen.

Yes. If someone touches a food containing an allergen and then touches another food, even a tiny amount of food protein can be transferred (moved from one food to the other). This can lead to an allergic reaction.

No. Cross-contamination happens when bacteria or germs from one food get on another food. This can make people sick. Cross contact occurs when an allergen is accidentally transferred from one food to another.

People may use these terms interchangeably, but cross-contact is the correct term for food allergies.

No. Cooking does not reliably remove or destroy food proteins that cause allergic reactions. Baked or fried foods can still contain allergens even after high heat. For example, cooking can change the shape of some egg proteins, making them tolerable for some but not all people allergic to eggs.

Use separate utensils, cutting boards and dishes for allergen-free foods. Wash your hands and surfaces with soap and water before preparing safe meals. Consider creating an allergen-safe zone in your kitchen so it’s organized.

Watch your child closely for any signs of an allergic reaction. Most allergic reactions occur within minutes of eating an allergen, but some can happen hours later. If you notice symptoms, especially affecting two or more body organs, follow your child’s anaphylaxis action plan. If symptoms are severe, use epinephrine right away.

Some food allergies don’t stop with a single trigger. Because certain foods share similar proteins, the immune system may “mix them up,” causing what’s known as cross-reactivity. This means a person allergic to one food could react to another, even if that person has never eaten it before.

  • Tree nuts are a common example: cashew and pistachio often cross-react, as do walnut and pecan. People allergic to hazelnut may also notice reactions if they have birch pollen allergy.
  • Peanuts, though legumes, can cross-react with soy, lentils, peas, and chickpeas. Still, most peanut-allergic individuals tolerate other legumes.
  • Cow’s milk allergies may overlap with goat’s or sheep’s milk, and sometimes even beef.
  • Egg allergy can extend to other bird eggs.
  • Fish allergies often span multiple species, while shellfish (shrimp, crab, lobster and crawfish) are strongly cross-reactive. Mollusks like clams and scallops may or may not overlap.

Oral Allergy Syndrome (OAS) happens when a person who is allergic to certain pollen (like birch, ragweed or grass) eats raw fruits, vegetables or nuts with similar proteins. OAS usually causes mild symptoms, like itching or tingling in the mouth, lips or throat. Cooking the food often breaks down the proteins and prevents a reaction.

OAS is very rare in infants and toddlers because it develops after years of pollen exposure. If your young child has these symptoms after eating a food, it is more likely a regular food allergy and should be evaluated by an allergist.