RESUMEN
Potato products prepared from dehydrated potato flakes have been implicated in foodborne illness incidents involving Bacillus cereus intoxications. B. cereus can survive as spores in potato flakes and can germinate and multiply in the rehydrated product. This study assessed the frequency and concentration of B. cereus in dehydrated potato flakes and hot-held, ready-to-eat mashed potato products. Of 50 packets of potato flakes tested, eight contained greater than 100 CFU/g B. cereus (maximum 370 CFU/g). The temperature of the potato portion of 44 hot-held food products was measured immediately after purchase, and 86% were below the safe hot-holding temperature of 60 degrees C. The potato portions were subsequently tested for B. cereus. Only two of the potato portions contained B. cereus at greater than 100 CFU/g, a potato-topped pastry (1000 CFU/g) and a container of potato and gravy (120 CFU/g). To assess multiplication of B. cereus in this food, we held rehydrated potato flakes with naturally occurring B. cereus at 37, 42, and 50 degrees C and tested them over 6 h. By 6 h, the number of B. cereus in potato stored at 37 degrees C had exceeded 10(3) CFU/g, was greater than 10(4) CFU/g at 50 degrees C, and was close to 10(6) CFU/g at 42 degrees C. Growth data were compared to predictions from the U.S. Department of Agriculture Pathogen Modeling Program (PMP 7.0). The PMP predictions were found to simulate the measured growth better at 42 degrees C than at 37 degrees C. Hot-held potato products should be safe for consumption if held at 60 degrees C or above or discarded within 2 h.
Asunto(s)
Bacillus cereus/crecimiento & desarrollo , Seguridad de Productos para el Consumidor , Manipulación de Alimentos/métodos , Solanum tuberosum/microbiología , Esporas Bacterianas/crecimiento & desarrollo , Bacillus cereus/aislamiento & purificación , Bacillus cereus/metabolismo , Bacillus cereus/fisiología , Recuento de Colonia Microbiana , Enterotoxinas/biosíntesis , Microbiología de Alimentos , Humanos , Nueva Zelanda , Temperatura , Factores de TiempoRESUMEN
Isoflavones present in soy may have risk and benefits to human health. Human gut microflora have been shown to exert metabolic activities on isoflavones, which influences bioavailability and bioactivity. Absorption of isoflavones is likely to occur in the small intestine where there is a diverse range of microfloral species able to hydrolyze conjugated isoflavones, releasing the bioactive aglycone for absorption or further metabolism and reconjugation. The identification of gut microbes that metabolize isoflavone aglycones is not well established. Such information may lead to a better understanding of the bioavailability of isoflavones in functional foods.
