Mysterious Outbreaks of Gastrointestinal Illness Associated with Burritos Supplied through School Lunch Programs

Abstract

From October 1997 through March 1998, three outbreaks of gastrointestinal illness among school children were linked to company A burritos. In September 1998, a similar outbreak occurred in three North Dakota schools following lunches that included company B burritos. We conducted an investigation to determine the source of the North Dakota outbreak, identify other similar outbreaks, characterize the illness, and gather evidence about the cause. The investigation included epidemiologic analyses, environmental investigation, and laboratory analyses. In North Dakota, a case was defined as nausea, headache, abdominal cramps, vomiting, or diarrhea after lunch on 16 September 1998. Case definitions varied in the other states. In North Dakota, 504 students and staff met the case definition; predominant symptoms were nausea (72%), headache (68%), abdominal cramps (54%), vomiting (24%), and diarrhea (16%). The median incubation period was 35 min and median duration of illness was 6 h. Eating burritos was significantly associated with illness (odds ratio, 2.6; 95% confidence interval, 1.6 to 4.2). We identified 16 outbreaks that occurred in seven states from October 1997 through October 1998, affecting more than 1,900 people who ate burritos from two unrelated companies. All tortillas were made with wheat flour, but the fillings differed, suggesting that tortillas contained the etiologic agent. Results of plant inspections, tracebacks, and laboratory investigations were unrevealing. More than two million pounds of burritos were recalled or held from distribution. The short incubation period, symptoms, and laboratory data suggest that these outbreaks were caused by an undetected toxin or an agent not previously associated with this clinical syndrome. Mass psychogenic illness is an unlikely explanation because of the large number of sites where outbreaks occurred over a short period, the similarity of symptoms, the common food item, the lack of publicity, and the link to only two companies. A network of laboratories that can rapidly identify known and screen for unknown agents in food is a critical part of protecting the food supply against natural and intentional contamination.

Modeling the emetic potencies of food-borne trichothecenes by benchmark dose methodology

“…From October 1997 to October 1998 there were 16 outbreaks of gastrointestinal illness affecting more than 1,900 school children following the ingestion of burritos from two unrelated companies (Steinberg et al, 2006). The children who consumed the burritos suffered nausea, headache, abdominal cramps, vomiting, and diarrhea.…”

Multiple Outbreaks of Gastrointestinal Illness Among School Children Associated with Consumption of Flour Tortillas—Massachusetts, 2003-2004

“…These outbreaks were similar to previously reported outbreaks of vomiting associated with burritos served in lunches at schools in the United States in 1997-1998. 1,2 The clinical characteristics reported in all of these outbreaks are consistent with exposure to an as yet unidentified pre-formed toxin or chemical agent. In such outbreaks, rapidly obtaining epidemiologic data and clinical and food samples is essential to determining illness etiology.…”

“…The clinical and epidemiologic characteristics of the outbreaks were similar to those of previously reported outbreaks of vomiting associated with burritos served at multiple schools in the United States in 1997-1998. 1,2 Epidemiologic investigation of the 1997-1998 outbreaks implicated burritos made with flour tortillas as the suspect vehicle; no etiologic agent was identified, but symptoms suggested either a biotoxin or chemical agent. This report describes epidemiologic and laboratory findings from three of the 10 outbreaks in Massachusetts.…”

Mycotoxin incidents associated with cereals: lessons learnt and risk reduction strategies

“…Both companies used wheat flour to make the tortillas; furthermore, all burritos were distributed to six of the seven affected States as frozen pre-packed product apart from Florida where the fillings were prepared locally. The outbreaks affected 1908 persons from 125 schools (Steinberg et al, 2006) Symptoms include nausea, vomiting, headache and abdominal cramps and occurred within an hour of consuming a burrito. Although no one was hospitalised and no one died, this group of incidents showed how epidemiological patient studies can be used to determine the likely cause of such illnesses.…”

“…In this incident, traceability systems and associated records were crucial. Limited shipping records for affected burritos may have hampered further investigation as some lots were not listed (Steinberg et al, 2006). Within the US food industry this may be enforced for high risk foods by legislation mandating the need for hazard analysis critical control point (HACCP) plans or may be a condition of supply under a number of global and national private food standards (Baines 2009).…”