FOOD SAFETY AND QUALITY ASSURANCE: ALLERGEN MANAGEMENT
Diagram
Food allergy: the immune path
First meeting: the protein enters through gut or skin. Sensitisation: the immune system makes IgE against that protein, with no symptoms yet. Later meeting: the protein links IgE together on mast cells. The mast cell releases histamine. Symptoms appear: itching, swelling, cramps, wheezing, or anaphylaxis.
Food intolerance: no immune path
The body cannot properly digest a food, or the food irritates the gut. Example: lactose intolerance, where a lack of the enzyme lactase leaves milk sugar undigested, so it ferments in the gut and causes bloating, wind, and diarrhoea. No IgE, no mast cells, no anaphylaxis.
Figure 1: Allergy runs through the immune system and IgE; intolerance runs through digestion and dose, with no immune response.
Introduction
Food allergy and food intolerance are often mixed up because some symptoms look alike, but they are different conditions and the mix-up can cause real harm. A food allergy is an immune response: the immune system mistakes a food protein for a threat, makes IgE antibodies against it, and reacts fast, sometimes with anaphylaxis. A food intolerance does not involve the immune system: the body cannot properly digest a food, such as when a lack of the enzyme lactase leaves milk sugar undigested, and the result is discomfort that depends on the amount eaten. In short, allergy is the immune system overreacting, and intolerance is digestion failing to cope.
Table 1: Quick comparison of food allergen and food intolerance
| Aspect | Food allergy | Food intolerance |
|---|---|---|
| What it is | An immune response to a food protein | A reaction that does not involve the immune system |
| Mechanism | IgE antibodies on mast cells; the protein links IgE together and histamine is released | Enzyme lack, such as missing lactase, or irritation of the gut |
| Onset | Fast, usually within minutes | Delayed, hours to a day or more, mainly in the gut |
| Dose | A very small amount can set off a reaction | Depends on amount: a small amount may be tolerated |
| Severity | Can be life threatening: anaphylaxis, with falling blood pressure and hard breathing | Uncomfortable but rarely life threatening |
| Symptoms | Skin, gut, airways, and blood pressure: hives, swelling, cramps, vomiting, wheezing | Mainly gut: bloating, wind, cramps, and diarrhoea |
| Example | Peanut, prawn, egg, or milk protein setting off an IgE reaction | Lactose intolerance from a lack of lactase |
| Test | Doctors use history, skin prick tests, blood IgE tests, and supervised food challenges | Doctors use history and clinical tests; food workers do not diagnose |
| Kitchen care | Strict avoidance, clean tools, and no guessing; follow the person’s own medical plan | Serve what the customer asks for, be honest about what can be guaranteed, and keep portions as asked |
Scientific explanation
Definition
A food allergy is an IgE driven immune response. The immune system meets a food protein, learns to treat it as a threat, and makes IgE antibodies against it, a silent stage called sensitisation. When the food is eaten again, the protein links IgE together on mast cells in the skin, gut, and airways, and the mast cell releases histamine and other chemicals. A food intolerance is not driven by IgE. Lactose intolerance is caused by a lack of the enzyme lactase, which breaks down milk sugar, so undigested lactose ferments in the gut and causes bloating, wind, and diarrhoea. It depends on amount, it does not affect breathing, and it is not life threatening, though it is uncomfortable and real.
Working principle
Allergy works through the adaptive arm of the immune system, which learns and remembers. B cells make IgE antibodies that fit one protein shape, and mast cells carry that IgE like a guard holding a photograph of one intruder. On the next meeting, the protein links the IgE, histamine widens blood vessels, makes them leak fluid, and irritates nerve endings, which explains redness, swelling, itching, cramps, and wheezing. A second phase can follow hours later as other white blood cells arrive. Intolerance works through digestion: without enough lactase, milk sugar is not broken down, so gut microbes ferment it and gas and loose stools follow. Coeliac disease is a third path, neither allergy nor intolerance: an immune response to gluten that damages the gut lining over days and weeks.
Apparatus
Allergy testing belongs to doctors: a skin prick test, a blood test that measures IgE to a food, and sometimes a supervised food challenge in a clinic where emergency care is ready. A food challenge must never be tried at home or in a restaurant. Intolerance is also a matter for doctors, not food workers.
Measurement procedure
Doctors read tests together with a careful history: what was eaten, how much, how soon symptoms started, and what the symptoms were. Neither test on its own proves a food allergy: a person can have IgE to a food and eat it without trouble. Food workers do not diagnose; they note what was eaten, when symptoms started, and what the symptoms were, and they pass that record to the medical team.
Factors affecting readings
Reaction strength changes with the amount eaten, the form of the food, and the state of the body. Raw or lightly cooked protein often keeps more of its shape than well cooked protein. Exercise, illness, lack of sleep, and alcohol can lower the threshold, so a food that caused only itching on a quiet day can cause a stronger reaction on a day when the person is unwell. Peanut proteins survive heat, acid, and enzymes well, which is one reason peanut allergy is often severe and long lasting.
Formulas and calculations
This topic has no standard formula in the books used for this article, so no worked example is given here. Do not use a made up formula for this topic.
Industrial applications
- Food allergy: allergen labelling, segregation of ingredients, cleaning between runs, supplier allergen checks, and staff training in factories and kitchens.
- Food intolerance: clear labelling of ingredients such as lactose, honest answers about recipes, and lactose free product lines.
- Both: a kitchen that hears ‘I cannot eat wheat’ must ask which it is, or treat it with the care that covers all of them: strict avoidance, clean tools, and no guessing.
Advantages and limitations
Allergy care advantages: strict avoidance and clean preparation prevent reactions, and a written plan plus an auto-injector give a clear emergency step. Limitations: a kitchen cannot promise a food is free of every trace of an allergen unless it has the controls to back that promise, and it must say so plainly.
Intolerance care advantages: dose matters, so small amounts and careful portions often work, and labelling lets the eater choose. Limitations: symptoms are real and uncomfortable, and a worker must never dismiss them as unimportant.
FAQ
Can a person eat peanuts for years and then react?
Yes. Sensitisation is silent, so a person can be sensitised and not know it until the day a reaction happens.
Is coeliac disease a food allergy?
No. Coeliac disease is an immune response to gluten, but it is not an IgE allergy. It damages the gut lining over days and weeks, and the person must avoid gluten strictly.
Why does an allergic reaction often start within minutes?
Because the mast cells are already armed with IgE and only need the protein to arrive. A reaction that starts several hours later may be a different kind of response, and a doctor is the person to sort that out.
What should a food worker ask when a customer says ‘I cannot eat wheat’?
Ask a simple question: ‘Is it an allergy, and what happens when you eat it?’ The answer tells the worker how urgent the care must be.
References and further reading
- FTN subject Food Allergen Management, Unit 1: Major Allergens and Why They Matter, and Unit 2: How Allergy Works: The Immune Response, including the allergy, intolerance, and coeliac disease comparison.
- FTN subject Food Safety and Security, Unit 1: What Food Safety Means, Hazards and Risk, section on infection, intoxication, and allergy.
- Book on disk: Food Quality Assurance: Principles and Practices; and Food Microbiology.
- Google Books: Food and Drink: Good Manufacturing Practice, books.google.com/books?id=KugWswD7ESQC, chapter on food allergens.
