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Fumonisin B 1 (FB 1 ) is a mycotoxin that commonly occurs in maize. FB 1 causes a variety of toxic effects in different animal species and has been implicated as a contributing factor of esophageal cancers in humans. In the present study, we examined the effect of dietary exposure to FB 1 on intestinal colonization by pathogenic Escherichia coli associated with extraintestinal infection. Three-week-old weaned pigs were given FB 1 by gavage as a crude extract or as a purified toxin at a dose of 0.5 mg/kg of body weight daily for 6 days. On the last day of the toxin treatment, the pigs were orally inoculated with an extraintestinal pathogenic E. coli strain. All animals were euthanized 24 h later, necropsies were performed, and tissues were taken for bacterial counts and light microscopic examination. Ingestion of FB 1 had only a minimal effect on animal weight gain, did not cause any macroscopic or microscopic lesions, and did not change the plasma biochemical profile. However, colonization of the small and large intestines by an extraintestinal pathogenic E. coli strain was significantly increased. Our results show that FB 1 is a predisposing factor to infectious disease and that the pig can be used as a model for the study of the consequences of ingesting mycotoxin-contaminated food.

The decomposition of ochratoxin A (OTA) was examined, under different temperature and moisture conditions. The calculated half-lives, corresponding to 50% values, were 707, 201, 12, and 6 min, respectively, at 100, 150, 200, and 250؇C for dry wheat and 145, 60, and 19 min, respectively, at 100, 150, and 200؇C for wheat heated under wet conditions. The presence of water (50%) increased the decomposition of OTA at 100 and 150؇C; the opposite was observed at 200؇C. Complete destruction of OTA within the limits of this study (100 to 250؇C) was not obtained.

Fumonisin B1 (FB1) is a mycotoxin from Fusarium moniliforme that is frequently associated with corn. Thermal treatments are used in many processes concerning this cereal and its derivatives. The thermostablity of this toxin in dry contaminated corn, resulting from F. monUiforme culture, was studied in different time-temperature combinations. FB1 was quantified by instrumentalized thin-layer chromatography after a two-step sequential development and postchromatographic derivatization byp-anisaldehyde. The identity of FB1 in extracts, before and after heat treatments, was confirmed by high-pressure liquid chromatography. For each temperature, the natural logarithm of the ratio of resulting FB1 on initial content (In C/Co) is linearly correlated to exposure time. The calculated half-lives (L50), corresponding to the 50%o value, were 10 min, 38 min, 175 min, and 8 h at 150, 125, 100, and 75°C, respectively. There is a linear relationship between calculated Lsos on a logarithmic scale and temperature. Therefore FB1 is not significantly destroyed by the main drying processes of corn or thermal treatments used for its derivatives. Other associated means are required for detoxification.

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