Care must be taken in the kitchen to avoid contact between allergenic and allergy-safe foods. For instance, while you’re cooking, sauce from an allergenic food could splatter onto an allergy-free food. Or there might be cross-contact, which is what happens when one food comes into contact with another, causing their proteins to mix. As a result of cross-contact, each food contains small amounts of the other food that may be invisible to us. For example, if a knife that has been used to spread peanut butter is only wiped clean before being used to spread jelly, there could be enough peanut protein remaining on the knife to cause a reaction in a person who has a peanut allergy. That's why all equipment and utensils should be cleaned with hot, soapy water before being used to prepare allergen-free food.
Even a trace of food on a spoon or spatula that is invisible to us can cause an allergic reaction.
To effectively remove food protein from surfaces, wash the surfaces with soap and water. Simply wiping the crumbs from spatulas, cookie sheets, or surfaces is not enough. To be safe, buy an extra cutting board to be used for allergy-free foods only, or use a disposable plate.
Studies have shown that conventional cleaning methods are effective in removing the protein of a food allergen such as peanut. Bar and liquid soap is effective for removing the protein from your hands, while alcohol-based sanitizer is not, according to a study published in the Journal of Allergy and Clinical Immunology1. That study also showed soaps and commercial cleaning agents effectively removed peanut protein from table tops, while dishwashing liquid alone did not.
When cooking allergen-free meals, use utensils and pans that have been thoroughly washed with soap and water. If you’re cooking several foods at the same time, cook the allergen-free meal first, then keep it covered and away from any splatter caused by other foods that are cooking. If you have handled an allergenic food, wash your hands with soap and warm water before serving the allergen-free meal.
1. Distribution of peanut allergen in the environment. Perry TT, Conover-Walker MK, Pomes A, Chapman MD, Wood RA. J.Clin Immunol, Vol. 113, No. 5.