Gastrointestinal Illness Associated with Consumption of a Soy Protein Extender ¹

In July and August 1976, an outbreak of acute gastrointestinal illness occurred among persons who had consumed a commercially marketed soy protein tunafish salad extender. After a public warning of a possible product contamination, representatives of 350 households reported 508 persons ill with an afebrile gastrointestinal syndrome that occurred usually within 1 h after the salad-extender was eaten. Interviews of randomly selected reported ill persons (cases) showed that the principal symptoms were nausea (91%), abdominal cramps (71%), diarrhea (53%), headache (42%), difficulty breathing (36%), and vomiting (22%). A survey of persons in the community who had eaten tuna extender revealed an illness attack rate (5.1%), which was significantly higher than the background incidence of gastrointestinal illness (1.1%) in persons who did not eat the tuna extender (p < .05). A case-control study showed that significantly more cases than controls had a history of "allergy" (p < .02). Tests of the product prepared by the manufacturer with volunteers implicated texturized soy protein as the cause of the illness. The findings in this study demonstrated that consumption of textured soy protein may elicit an adverse gastrointestinal response in a small but significant number of individuals, especially those with a history of "allergy."