Resumen El objetivo del estudio fue predecir el riesgo potencial de exposición a V. cholerae y V. parahaemolyticus asociado al consumo de ostión americano (Crassostrea virginica) crudo colectado del Sistema Lagunar Mandinga (SLM), en restaurantes, coctelerías y puestos ambulantes. El riesgo se estimó como casos esperados/100,000 porciones con el modelo de la FDA. En ostiones del SLM el riesgo estimado por consumir ostiones contaminados con V. cholerae noO1/noO139 chxA+ sin refrigerar 10 h en verano fue bajo (99×10-5 casos); V. parahaemolyticus tdh+ y tdh+/trh+ representaron un riesgo estimado alto en primavera (2,200×10-5 y 4,000×10-5 casos, respectivamente) y la cepa pandémica orf8+ un riesgo medio (110×10-5 casos) en invierno. El consumo de ostión crudo sin refrigerar 10 h contaminado con V. cholerae noO1/noO139 chxA+ representó un riesgo promedio bajo (0.87×10-5 y 0.44×10-5 casos) para restaurantes y coctelerías, respectivamente, alto para cocteles expendidos en puestos ambulantes a temperatura ambiente 24 h (2,500×10-5 casos) y bajo a V. parahaemolyticus tdh+ en restaurantes (0.21×10-5 casos) y coctelerías (1.1×10-5 casos). El porcentaje patogénico, el sitio de venta y el tiempo sin refrigerar fueron las variables que incrementaron el riesgo de enfermar, siendo primavera la estación con el mayor riesgo para el consumidor.

Abstract The aim of the study was to assess the potential risk of exposure to V. cholerae and V. parahaemolyticus associated to raw American oyster (Crassostrea virginica) consumption collected from the Mandinga Lagoon System (MLS), in restaurants, oyster bars, and street vendors. Risk was estimated as number of cases/100,000 servings with FDA model. The risk of oyster consumption from MLS contaminated with V. cholerae noO1/noO139 chxA+ and unrefrigerated 10-h was low (99 × 10-5 cases) in summer; V. parahaemolyticus tdh+ y tdh+/trh+ estimated risk was high in spring (2,200 × 10-5 y 4,000 × 10-5 cases, respectively) and the pandemic strain orf8+ risk was medium in winter (110 × 10-5 cases). Oyster cocktail consumption unrefrigerated for 10 h and contaminated with V. cholerae noO1/noO139 chxA+, represented a low mean risk (0.87 × 10-5 and 0.44 × 10-5 cases) for oyster cocktails from restaurants and oyster bars, respectively, a high mean risk for street vendor cocktails stored at ambient temperature 24-h (2,500 × 10-5 cases), and a low mean risk for V. parahaemolyticus tdh+ in restaurants (0.21 × 10-5 cases) and oyster bar (1.1 x 10-5 cases) cocktails. Risk assessment results indicated that pathogenic percentage, type of establishment, and unrefrigerated storage time were variables that most increased the probability of illness, and spring the season with the highest risk for consumers.

Abstract Vegetable oil deterioration during frying is a health problem because of oil degradation compounds and recycled oil practices are related to disturb oil quality. Frying food street-vendors are an important part of endemic market type Tianguis at the Metropolitan areas in the Central Highlands of Mexico. The main objective of this research was to evaluate frying edible vegetable oil quality from frying by street-food vendors in a Metropolitan area in the Central Highlands of Mexico. A behaviour questionary registered fresh and recycling oil addition, frying temperature and method in real operation conditions for three working days. Free fatty acid, colour, p-Anisidine, peroxide, and TOTOX indexes were observed in the vendors by triplicate. Free fatty acids and peroxide values in two vendors exceeded the NMX-F-223-SCFI-2011 values. Physicochemical variables revealed oil oxidation deterioration. Not so high temperatures were registered, and continually fresh oil addition was suggested as mitigating or masking edible oil of thermal oxidation and its degradation agents during the observed time. Thermal oxidation could be lower than in controlled conditions as in many reports due to vendor operations studied as a real approximation that suggested less oil degradation. Present results could be evidence for government intervention in the regulation needs.

Abstract Dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) are endocrine disruptors whose presence in milk entails a health risk. There is evidence that pasteurization decreases or increases the concentration of organochlorine pesticides in dairy products. The present research evaluated the effect of pasteurization at 63 °C 30 min-1 and 73 °C 15 sec-1 on the concentrations of DDT, HCH and their metabolites in bovine milk, in order to estimate the dietary exposure from human consumption of pasteurized milk. A completely randomized experimental design with two treatments was performed on 100 milk samples collected in Soledad de Doblado and Jamapa, Veracruz, Mexico. Pesticides were quantified by gas chromatography with an electron microcapture detector. Data were analyzed by single-factor analysis of variance (P<0.05), and means were compared with Tukey’s test (P<0.05). The dietary exposure to pesticides was assessed based on the estimated daily intake (EDI) and average daily dose (ADD) in three population groups. Pasteurization at 73 ºC reduced the concentrations of p,p'-DDE, p,p'-DDD, o,p'-DDT, p,p'-DDT and total DDT by 30.94, 44.51, 3.18, 81.23, and 42.82 %, respectively, as well as the concentrations of β-HCH, γ-HCH and total HCH (by 85.68, 18.88, and 99.31 %, respectively). The EDI of total DDT by children, adults, and elderly people was lowest for consumption of milk pasteurized at 73 °C, and that of γ-HCH, for milk pasteurized at 63 °C. The DDP of total DDT decreased with pasteurization at 73 °C. The dietary exposure to DDT and HCH was higher in children.

Resumen El diclorodifeniltricloroetano (DDT) y hexaclorociclohexano (HCH) son disruptores endocrinos cuya presencia en la leche representa un riesgo para la salud. Existe evidencia de que la pasteurización disminuye o incrementa la concentración de plaguicidas organoclorados en productos lácteos. La presente investigación evaluó el efecto de la pasteurización a 63 °C 30 min-1 y 73 °C 15 seg-1 en las concentraciones de DDT, HCH y sus metabolitos en leche bovina, para estimar la exposición dietaria por consumo humano de leche pasteurizada. Se realizó un diseño experimental completamente al azar con dos tratamientos en 100 muestras de leche recolectadas en Soledad de Doblado y Jamapa, Veracruz, México. Los plaguicidas se cuantificaron por cromatografía de gases con detector de microcaptura de electrones. Los datos se analizaron mediante análisis de varianza unifactorial (P<0.05) y las medias se compararon con Tukey (P<0.05). La exposición dietaria a plaguicidas se evaluó por la ingesta diaria estimada (IDE) y dosis diaria promedio (DDP) en tres grupos de población. La pasteurización a 73 ºC disminuyó 30.94, 44.51, 3.18, 81.23 y 42.82 % las concentraciones de p,p'-DDE, p,p'-DDD, o,p'-DDT, p,p'-DDT y DDT total, respectivamente, así como las concentraciones de β-HCH, γ-HCH y HCH total (85.68, 18.88 y 99.31 %, respectivamente). La IDE para niños, adultos y ancianos de DDT total fue menor por consumo de leche pasteurizada a 73 ºC y de γ-HCH a 63 ºC. La DDP de DDT total disminuyó con la pasteurización a 73 °C. La exposición dietaria de DDT y HCH fue mayor en niños.

Objective. To quantify Vibrio parahaemolyticus densities in American oyster (Crassostrea virginica) under cold storage. Materials and methods. 320 oysters were stored at 7°C for nine days and total and pathogenic densities were determined by the NMP-PCR methodology. Results. V. parahaemolyticus tlh+ densities were observed on 0,3, and 6 days of storage at 1.134, 2.764 and 0.785 log10NMP/g, respectively, and pathogenic density trh+ on 0 and 3 days at 0.477 and 0.519 log10NMP/g, respectively; the pathogenic densities tdh+ (0.519 log10NMP/g), tdh+/trh+ (0.519 log10NMP/g), and tdh+orf8+ (-0.444 log10NMP/g) were detected on day 3 of storage. Conclusion.The results suggest that V. parahaemolyticus growth and pathogenic genes occurrence at 7°C involve changes in the genetic expression as a cold shock response, favoring V. parahaemolyticus survival and virulence, representing a health risk.

Objetivo. Cuantificar las densidades de Vibrio parahaemolyticus en ostión americano (Crassostrea virginica) almacenado en refrigeración. Material y métodos. Se almacenaron 320 ostiones a 7 °C durante nueve días y se determinaron las densidades totales y patogénicas mediante la técnica NMP-PCR. Resultados. Se observaron densidades de V. parahaemolyticus tlh+ en los días 0,3 y 6 de almacenamiento con 1. 134,2.764 y 0.785 log10NMP/g, respectivamente, y en los días 0 y 3 la densidad patogénica trh+ con 0.477 y 0.519 log10NMP/g, respectivamente; las densidades patogénicas tdh+ (0.519 log10NMP/g), tdh+/trh+ (0.519 log10 NMP/g) y tdh+/orf8+ (-0.444 log10NMP/g) se detectaron al tercer día de almacenamiento. Conclusión. Los resultados sugieren que el crecimiento de V. parahaemolyticus y la ocurrencia de genes patogénicos a 7 °C involucran cambios en la expresión génica como una respuesta al estrés por frío. Esto contribuye a la sobrevivencia y virulencia de V. parahaemolyticus, lo cual representa un riesgo a la salud pública.

Objective. To quantify Vibrio parahaemolyticus densities in American oyster (Crassostrea virginica) under cold storage. Materials and methods. 320 oysters were stored at 7°C for nine days and total and pathogenic densities were determined by the NMP-PCR methodology. Results. V. parahaemolyticus tlh+ densities were observed on 0,3, and 6 days of storage at 1.134, 2.764 and 0.785 log10NMP/g, respectively, and pathogenic density trh+ on 0 and 3 days at 0.477 and 0.519 log10NMP/g, respectively; the pathogenic densities tdh+ (0.519 log10NMP/g), tdh+/trh+ (0.519 log10NMP/g), and tdh+orf8+ (-0.444 log10NMP/g) were detected on day 3 of storage. Conclusion.The results suggest that V. parahaemolyticus growth and pathogenic genes occurrence at 7°C involve changes in the genetic expression as a cold shock response, favoring V. parahaemolyticus survival and virulence, representing a health risk.

Objetivo. Cuantificar las densidades de Vibrio parahaemolyticus en ostión americano (Crassostrea virginica) almacenado en refrigeración. Material y métodos. Se almacenaron 320 ostiones a 7 °C durante nueve días y se determinaron las densidades totales y patogénicas mediante la técnica NMP-PCR. Resultados. Se observaron densidades de V. parahaemolyticus tlh+ en los días 0,3 y 6 de almacenamiento con 1. 134,2.764 y 0.785 log10NMP/g, respectivamente, y en los días 0 y 3 la densidad patogénica trh+ con 0.477 y 0.519 log10NMP/g, respectivamente; las densidades patogénicas tdh+ (0.519 log10NMP/g), tdh+/trh+ (0.519 log10 NMP/g) y tdh+/orf8+ (-0.444 log10NMP/g) se detectaron al tercer día de almacenamiento. Conclusión. Los resultados sugieren que el crecimiento de V. parahaemolyticus y la ocurrencia de genes patogénicos a 7 °C involucran cambios en la expresión génica como una respuesta al estrés por frío. Esto contribuye a la sobrevivencia y virulencia de V. parahaemolyticus, lo cual representa un riesgo a la salud pública.