1. A common allergenic protein may be combined with another product. This can create a new allergic reaction in the genetically modified product. Almost every food type causes allergic reactions within at least a few people, but the most allergenic foods include: fish, milk products, fruits, eggs, wheat and nuts (van Dam et al. 1996).

When genes are combined, it is difficult for consumers to trace allergens, and products can become dangerous for a portion of the population. For example, in Brazil soybeans were combined with Brazil nuts. During preliminary testing, Brazil nut-spliced soybeans turned up allergenic-negative. The soybeans then created strong allergic reactions for those people allergic to Brazil nuts. These people, never previously having had problems eating soy-products, unknowingly ingested the genes of the nuts (Nordlee et al., 1996).

2. New allergens can also be created through the process of genetic engineering. Proteins that are not usually used in food products are introduced, which can create and develop new allergens of which people are not aware (van Dam et al. 1996).

Naturally safe products can become allergenic or toxic. A very serious example of this possibility was when four genes were added to a bacterium of the amino acid tryptophan. These tablets developed highly toxic substances that killed 37 people and left more than 1, 500 with autoimmune and neurological disorders in 1988 (Fagan 1996).

Without adequate testing and labeling of these altered products, it is difficult for consumers to trace food allergens and prevent allergic reactions, which range from mild effects to sudden death.