First genotyping of Blastocystis sp. in dairy, meat, and cashmere goats in northwestern China.

Blastocystis is one of the most common parasites inhabiting in small intestines of human and animals. Although its pathogenicity has been remaining controversial, the possibility of zoonotic transmission between human and animals was recognized. The goat was one of the most important economic animals supplying people with cashmere, meat, and dairy products. However, few studies were to investigate Blastocystis infection in goats. A total of 789 faecal specimens of goats (including 362 of dairy, 193 of meat and 234 of cashmere goats) were collected from multiple regions of Shaanxi province in northwestern China to investigate the colonization frequency and subtypes of Blastocystis, and to assess the zoonotic potential of these goats. The respective colonization frequencies of Blastocystis in dairy, meat and cashmere goats were 54.1% (196/362), 40.4% (78/193) and 78.6% (184/234). The prevalence of Blastocystis in pre-weaned (0-2-month) goats was significantly lower than that in goats of other age groups, and the highest colonization was observed in goats of 7-11-month age group. Sequence analysis of Blastocystis positive samples indicated the presence of seven subtypes in these goats, including six known subtypes (STs1, 3, 4, 5, 10, 14) and one possible novel subtype (isolate Sd26), with the subtype 10 as the predominant one. Additionally, zoonotic subtypes were found in dairy (ST1, ST3 and ST5) and cashmere (ST4 and ST5) goats, but not detected in meat goats. These results showed that Blastocystis is highly prevalent, widely distributed and genetically diverse in goats in Shaanxi province, northwestern China, and zoonotic potential of dairy and cashmere goats to transmit Blastocystis.

Principles and applications of hyperspectral imaging in quality evaluation of agro-food products: a review.

The requirements of reliability, expeditiousness, accuracy, consistency, and simplicity for quality assessment of food products encouraged the development of non-destructive technologies to meet the demands of consumers to obtain superior food qualities. Hyperspectral imaging is one of the most promising techniques currently investigated for quality evaluation purposes in numerous sorts of applications. The main advantage of the hyperspectral imaging system is its aptitude to incorporate both spectroscopy and imaging techniques not only to make a direct assessment of different components simultaneously but also to locate the spatial distribution of such components in the tested products. Associated with multivariate analysis protocols, hyperspectral imaging shows a convinced attitude to be dominated in food authentication and analysis in future. The marvellous potential of the hyperspectral imaging technique as a non-destructive tool has driven the development of more sophisticated hyperspectral imaging systems in food applications. The aim of this review is to give detailed outlines about the theory and principles of hyperspectral imaging and to focus primarily on its applications in the field of quality evaluation of agro-food products as well as its future applicability in modern food industries and research.

Effects of temperature and different food matrices on Cyclospora cayetanensis oocyst sporulation.

Effects of temperature on the sporulation of the parasite Cyclospora cayetanensis were studied in 2 food substrates, dairy and basil. Unsporulated Cyclospora oocysts were subjected to freezing and heating conditions for time periods ranging from 15 min to 1 wk. Oocysts were then removed from the food substrates and placed in 2.5% potassium dichromate for 2 wk to allow viable unsporulated oocysts to differentiate and fully sporulate, and to determine the percentage sporulation as an indicator of viability. Sporulation occurred when oocysts resuspended in dairy substrates were stored within 24 hr at -15 C. When oocysts were placed in water or basil, sporulation occurred after incubation for up to 2 days at -20 C, and up to 4 days at 37 C. Few oocysts sporulated when incubated for 1 hr at 50 C. Sporulation was not observed in basil leaves or water at -70 C, 70 C, and 100 C. Sporulation was not affected when incubated at 4 C and 23 C for up to 1 wk, which was the duration of the experiment in both of the tested substrates.

Frecuencia de Listeria monocytogenes en derivados lácteos analizados en el Laboratorio de Salud Pública de la Secretaría Distrital de Salud de Bogotá en 2001 y 2002 / Frequency of Listeria monocytogenes in dairy products analyzed at the Public Health Laboratory of the District Health Secretariat of Bogota in 2001 and 2002

Durante los años 2001 y 2002, se analizaron derivados lácteos en el Laboratorio de Salud Pública (LSP) de la Secretaría Distrital de Salud (SDS) de Bogotá, que dieron como resultado cultivo positivo para Listeria monocytogenes, lo cual constituye un problema de salud pública, debido a la población de riesgo que afecta a maternas, niños, ancianos e inmunosuprimidos. Para determinar la frecuencia de L. monocytogenes en los derivados lácteos se utilizaron los registros de la base de datos correspondiente al análisis de estos alimentos en el LSP de la SDS de Bogotá durante 2001 y 2002; posteriormente se cruzaron las variables clase de derivado lácteo, hospital, causa de no aceptabilidad, objeto de muestreo y fosfatasa alcalina. La frecuencia de L. monocytogenes en los derivados lácteos fue para el 2001 del 6% y para el 2002, del 3%. Los alimentos más involucrados en la contaminación por este microorganismo fueron las cremas de leche y los quesos. En el 2001, sólo el 29% de los derivados lácteos contaminados por L. monocytogenes correspondieron a fosfatasa alcalina positiva, y en el 2002 fue del 24%. No existe relación directa entre la positividad de la fosfatasa alcalina con la presencia de L. monocytogenes en los derivados lácteos, y posiblemente la contaminación por este microorganismo sucedió después de la elaboración del producto o porque las células de L. monocytogenes pueden sobrevivir al tratamiento de pasteurización cuando se encuentran incluidas en los glóbulos grasos de la leche. Los resultados obtenidos en este estudio sirven para orientar el muestreo con enfoque de riesgo por parte de los hospitales en los derivados lácteos.

During 2001 and 2002, dairy products were analyzed at the Public Health Laboratory (LSP) of the District Health Secretariat (SDS) of Bogota, which resulted in positive cultures for Listeria monocytogenes, which constitutes a public health problem, due to the population at risk that affects mothers, children, the elderly, and the immunosuppressed. To determine the frequency of L. monocytogenes in dairy products, the records of the database corresponding to the analysis of these foods in the LSP of the SDS of Bogotá during 2001 and 2002 were used; subsequently, the variables class of dairy product, hospital, cause of unacceptability, object of sampling and alkaline phosphatase were crossed. The frequency of L. monocytogenes in dairy products was 6% in 2001 and 3% in 2002. The foods most involved in contamination by this microorganism were milk creams and cheeses. In 2001, only 29% of the dairy products contaminated by L. monocytogenes had positive alkaline phosphatase, and in 2002 it was 24%. There is no direct relationship between alkaline phosphatase positivity and the presence of L. monocytogenes in dairy products, and possibly the contamination by this microorganism occurred after the processing of the product or because L. monocytogenes cells can survive pasteurization treatment when they are included in the fat globules of the milk. The results obtained in this study serve to guide risk-based sampling by hospitals in dairy products.

Identification of lactic acid bacterial and enterobacteria: a technique in microplates

En este trabajo se desarrolla una microtécnica para la identificación de bacterias lácticas y bacterias enteropatogénicas. Los resultados fueron comparados con los obtenidos por el método convencional. se logró una reducción del volumen final y del tiempo de incubación para el estudio de fermentación de azúcares y otras propiedades bioquímicas en comparación con el ensayo tradicional. La correlación obtenida entre el ensayo en microplaca y el método convencional fue superior al 90 por ciento. La preparación de las microplacas con los diferentes reactivos pueden ser conservadas bajo condiciones de refrigeración durante 30 días antes de su empleo. La microtécnica puede ser considerada como un método sencillo, rápido y económico

Cryptosporidium parvum studies with dairy products.

Cryptosporidium parvum is a protozoan parasite capable of causing massive waterborne outbreaks. This study was conducted to model the transfer of C. parvum oocysts from contaminated water via food contact surfaces into yogurt and ice-cream, as well as to examine oocyst survival. Propidium iodide staining, combined with a direct immunofluorescence assay, was used for oocyst viability determination. Oocysts were recovered from milk products by a sucrose flotation-based procedure, with average recoveries of 82.3, 60.7, and 62.5% from low (1%) fat milk, 9% fat ice-cream, and 98% fat-free yogurt, respectively. Oocysts were also recovered, by rinsing with tap water, from stainless steel surfaces inoculated with oocyst suspension, with average recoveries of 93.1% when the surface was still wet and 69.0% after the surface had air-dried at room temperature. Viability of oocysts on the surface was significantly affected by desiccation; 5% of the oocysts remained viable after 4 h of air-drying at room temperature, while the proportion of viable oocysts was 81, 69, and 45% after air-drying for 10 min, 1 h, and 2 h, respectively. In contrast, oocyst viability only dropped from 82 to 75% after 30 min contact at room temperature with 5% bleach solution (equivalent to 0.26% NaOCl). Transfer of oocysts from milk and stainless steel surfaces into yogurt, and oocyst survival during the process were analyzed. Yogurt was made from pasteurized low fat milk and live yogurt starter by incubating at 37 degrees C for 48 h and then stored at 4 degrees C. Oocyst viability decreased from 83% (80%) to approximately 60% after 48 h at 37 degrees C and to approximately 58% following 8 days of storage, similar to oocyst survival in the controls using pasteurized milk without the addition of live yogurt. Oocyst survival in ice-cream was investigated by inoculating oocysts into ice-cream mix, and mixing and freezing in an ice-cream freezer, and hardening at -20 degrees C. Although approximately 20% (25 and 18%) of oocysts were viable before hardening, none were viable after 24 h at -20 degrees C. Control samples of oocysts suspended in distilled water and stored at -20 degrees C were taken at the same time intervals and 8% of the oocysts were still viable after 24 h.

Risks and prevention of contamination of dairy products.

Consumers and regulatory officials are becoming increasingly aware of the human health risk of the presence of micro-organisms or chemicals in the agricultural environment. Providing 'on-farm food safety' programmes which address the daily management of the production unit with regard to animal health and well-being, public health and environmental health must be a top priority for agriculturalists and veterinarians. Developing critical control point management (CCPM) procedures for animal and human health concerns is a viable approach to aid in alleviating public concerns about dairy products and the food supply in general. Such CCPM programmes may be created for individual production units based upon risk analysis, total quality management and hazard analysis and critical control point principles. Implementation of these programmes will be essential both in addressing food safety concerns for the resident population of a nation and in developing or maintaining international markets for the export of animal products.

[Experimental Trypanosoma cruzi infection via contaminated water and food]. / Infección experimental con Trypanosoma cruzi a través de agua y alimentos contaminados.

In order to determine the efficiency of different foods and water to maintain the infectivity of T. cruzi, the percentage of animals that resulted infected when they were ingested was registered. The materials were contaminated with metacyclic trypomastigotes from triatomine bugs feces, the infection in the mice were registered by directed observation of the parasite in the blood and corroborate by xenodiagnosis. Pasteurized milk infected the highest number of mice and the infectivity lasted longer than any other item tested. The efficacy of infectivity of fresh cheese and rice lasted after three hours and the percentage of infected mice was lower than with milk. Cooked and raw beefmeal and water resulted in the lowest, although similar number of infected mice. The infective capacity lasted only for a short time. It appears that the main differences obtained in infectivity depended on the different contents of moisture and nutrients in the solution.