Saylor and Bahna, 1991). Maillard reaction products in milk are reported to have increased allergenicity in skin tests (Maleki, 2004). Allergic reactions have also been reported involving both hard and soft cheeses (Besler et al., 2001).
Egg. Both soft and hard boiling of eggs decreased, but did not eliminate, antigen binding of rabbit antiserum to ovomucoid and ovalbumin (Besler et al., 2001). Heated egg white showed a 58% decrease in IgE binding in RAST (Anet et al., 1985). A decrease in positive reactions was seen with heated egg white in 55% of egg allergic patients using DBPCFC (Urisu et al., 1997). There are reports of allergic reaction to egg contained in cooked meatballs or hamburger (Sampson et al., 1992b; Besler et al., 2001).
Fish. Boiling ten species of fish failed to eliminate allergenicity in DBPCFC (Bernhisel- Bradbent et al., 1992b). IgE binding to fish proteins in immunoblots was reduced, but not eliminated. Canning (presumably due to the heat processing) appears to reduce allergic reactions to tuna and salmon in allergic patients tested by DBPCFC (Bernhisel- Broadbent et al., 1992b). IgE binding of allergenic proteins from canned fish was reduced by 98 to 99% compared to boiled fish. IgE binding studies indicate that fish allergens are present in surimi (Mata et al, 1994).
Shellfish. Boiling does not reduce the allergenicity of shrimp allergens (Daul et al., 1988; Naqpal et al., 1989).
Soy. Heating soybeans at 100ºC for 60 minutes does not completely eliminate IgE binding to allergenic soy proteins (Burks et al., 1992). Various soybean products including sprouts, soy sauce, hydrolyzed soy protein tofu, miso, and lecithin all retained IgE-binding activity (Besler et al., 2001). IgE binding proteins have been found in soy lecithin (Gu et al., 2001; Porras et al., 1985; Paschke et al., 2001). Allergic reactions to soy lecithin have also been reported (Renaud, 1996; Palm, 1999). The protein content of soy lecithin has been reported to vary between 2.8-202 mg per 100 g (Besler et al., 2001; Paschke et al., 2001). IgE binding proteins have been consistently detected in unrefined soybean oils (Paschke et. al., 2001), but inconsistently in refined oil (Awazuhara et al., 1998; Paschke et al., Errahali et al., 2002)
Tree nuts. Protein extracts of several hazelnut-containing products demonstrated less IgE binding than raw hazelnut aqueous extracts suggesting that heating reduced allergenicity. However, some IgE binding capacity remained (Wigotzki et al., 2001). Several cases of anaphylaxis have been described for a variety of processed nut-containing products, suggesting that tree nuts in general retain allergenic activity after heating (Besler et al., 2001). Roasting, blanching, autoclaving, or microwaving did not change the ability of animal antisera to bind almond proteins (Venkatachalam et al., 2002).
Wheat. Baking of wheat flour-containing foods results in the loss of IgE binding to one group of recognized wheat allergens, the alpha-amylase inhibitors. However, baking does not affect the ability of wheat prolamins to bind IgE from wheat allergic individuals (Simonato et al. 2001). The wheat allergen omega-5 gliadin also retains allergenic activity after cooking. For example, Daengsuwan et al. (2005) found IgE to omega-5
Revised Threshold Report Page 27 of 108