Soy Good to Know

As consumers, we all want the assurance that a food label accurately reflects the composition of the product enclosed. F.A.C.T.S. conducted a small-scale laboratory trial on four commercially available "soy-free" food products to see whether they are, in fact, free of what they ought to be!

Food allergies and intolerances are not a new phenomonen. As far back as 55 BC, the distinguished Latin poet and philosopher Lucretius wrote in his poem De Rerum Natura (On the Nature of Things): ‘What is food for some, may be fierce poison for others’. Now, more than 2000 years later, the growing number of individuals that suffer from adverse reactions to certain foods can certainly relate to this statement.

Food allergies are immune-mediated reactions to food or food components (normally proteins) that occur in certain individuals. While food allergies generally affect a small proportion of the population, an allergic reaction can be life threatening or fatal. The prevalence of food allergies is on the rise, and the distribution of food allergens is changing with the food consumption behaviour of the population. Over the past 20 years, the number of allergy cases has increased by 25%. The prevalence of food allergy is highest among infants and young children, ranging from 4-8% in this group. The eight main culprits estimated to produce approximately 90% of allergic reactions include wheat (gluten), egg, milk, crustacea, fish, peanuts, soybeans or tree nuts, or the products of these foods. Allergies in children to exotic fruit, legumes, oilseeds and mustard have also recently begun to make an appearance.

Soy allergy is one of the most common food allergies. This reaction can be caused by an immune response to any of the 15 allergenic proteins that have been identified in the soybean (Glycine max). The most severe reaction to this legume is anaphylaxis, which results in a rapid decrease in blood pressure, severe obstruction of the airways and multiple organ failure. This condition can be fatal if not treated within minutes. Soy allergy can also manifest itself in urticaria (hives), redness and rash (inflammation due to immune response) and eczema. The lowest threshold for soy allergens that may result in adverse reactions has not been determined but appears to be low (ppm levels). Ongoing research is required to elucidate these threshold values that can provoke a reaction from soy protein.

The cure for soy allergy

The role of the food industry

With the rise in both food allergy and allergen awareness, coupled with the increasingly strict food regulations worldwide, food manufacturers have come under increasing scrutiny with regard to their allergen control systems. The South African food industry is facing similar complex demands. These demands include providing safe foods for food allergic individuals, with labelling that clearly and completely reflects the food components present in the product.

In recent years, tests for certain allergenic foods have been commercialised, and have aided food manufacturers to detect and control allergens in the final food product. The methods most commonly utilised to test for food allergens are the Enzyme-Linked Immunosorbent Assay (ELISA) and the polymerase chain reaction (PCR). While there are many strategies that can be applied to control allergens in the food plant (many of which form part of a HACCP plan), the efficiency of these strategies can only be validated using accurate allergen detection methods. By measuring the content of specific allergenic residues on manufacturing equipment, in raw ingredients or in finished products, allergen risks can be assessed and allergen control systems can be verified.

What do the regulations say?

In South Africa, the regulations pertaining to the labeling of allergenic foodstuffs appear in the Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act No. 54 of 1972), with regards to the regulations on labelling and advertising of foodstuffs (R.2034/1993). According to the draft of this regulation published in the Government Gazette (20 July 2007), the presence of soy or soy derivatives in a food product must be clearly indicated on the label. In addition, where a food product does not contain soy as an ingredient, but the presence of soy in the product may be possible due to cross-contamination, appropriate precautionary labeling is required. The draft regulations also stipulate that a food product cannot bear claims of being “hypoallergenic " or "nonallergenic" unless it is not possible to detect any possible allergen by means of an ELISA assay.

The trial

With these regulations in mind, it was undertaken to test several commercially available food products for the presence of soy utilising a soy protein ELISA assay. The specific aim of conducting this trial was to validate the “soy-free” claims made on the packaging of these products. It was anticipated that by doing this, it would be possible to provide some positive reinforcement to the food industry and to consumers with regards to the status of the control and labelling of allergens in South Africa. The four “soy-free” products evaluated where obtained from a local retailer, and included an infant cereal, two instant baby food products and a cake mix.

The results

The results obtained from the ELISA test indicated that the levels of soy protein in all four products were below the detection limit of the ELISA test (0.5% soy protein). It was thus deduced that these products could have either contained zero or minute quantities of soy protein that were too low to be quantified by the ELISA test. In this instance, the “soy-free” claims made for these products were in line with the South African allergen labelling regulations for soy (below the detection limit of the ELISA test) in the draft food legislation.

Although a multitude of research remains to be done on allergies and allergen detection, it is believed that the enormous efforts made by researchers, as well as the utilisation of test kits by the food industry has already been successful in providing enhanced protection to allergic individuals. This will form a solid foundation for the development and improvement of the prevailing allergen control and detection systems.

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