Food allergy is a term which is widely used and a general misconception is that all reactions to food is allergy based. But, in reality it is not true. It is suggested that until actual food allergy is properly diagnosed, the term adverse food reaction should be used. AFR can be categorized as
a. Food hypersensitivity: It occurs when the immune system reacts to a substance (food) that is usually harmless because the immune system falsely consider it as harmful. Food allergy includes Immunoglobulin E (IgE) or Type I which can be reproducible through ‘cause-and-effect relationship’ and the reaction occurs within 2 hrs of exposure. Severity can vary from mild to fatal.
There is a long list of foods are considered as food allergen category but, few has been found to cause allergic reactions. Generally it has been found that the most common food allergens are food with high protein content eg. egg, fish, milk, peanuts, soy, wheat, shellfish etc. The allergens (antigens) in food are generally water soluble glycoproteins and many of them are unaffected by denaturation from heat and acid. The allergenicity of these antigens can be altered by heating. Antigens of some foods are even removed by processing. If we see, many of those allergic to peanuts are not allergic to peanut oil. Point should kept in mind that exposure to antigen is prerequisite for food allergy. Exposure to antigen sensitizes immune cells which further causes allergic reactions.
b. Food Intolerance: It is an adverse reaction to a food caused by toxic, pharamacologic, metabolic or idiosyncratic (unpredictable) reactions to food or chemical substance in food. This is non immunological in nature. Though the symptoms of food allergey and food intolerance may be similar but their treatments are different.
i. Food additives
Adverse reactions to coloring agents, preservatives, sodium nitrate, antioxidants has been reported but, the occurrence is rare. MSG (mono-sodium glutamate) shows adverse reactions such as headache, nausea, flushing etc. Still, role of MSG in such reactions is the topic of debate.
Sulphites has been reported to have adverse reactions. This is widely used in food and beverages to control browning and microbial growth. Asthmatic people are generallysensitive to sulphites.
ii. Lactose intolerance
Lactose intolerance is the condition found in person deficient in lactase enzyme (enzyme responsible for lactose digestion). It is very common case of intolerance where people show decreased ability to digest lactose present in milk which leads to abdominal crampin, flatulence, and diarrhea.
Being food technologist/food processor how can we control the contamination of food by allergens
1. Proper cleaning should be ensured between manufacturing of two different foods in same equipment
2. Misleading labels should be avoided
3. In ingredient declaration, the ingredient should be listed as specific ingredient rather than as general terms of their purpose. For eg. egg should be listed as ‘egg’ not as ‘emulsifier’
4. When we switch from one ingredient to another (for any reason), we should properly study the adverse reaction of new ingredient. For eg, if we plan to switch from milk protein to wheat protein in emulsion preparation, we need to study the adverse reaction of wheat properly.
Latex allergy report has increased since early 90s. Symptoms include dermatitis and immediate allergy reactions. Cross-reactivity between latex and multiple food must be avoided. So, latex should not be worn while preparing foods for these individuals.