Impact of irrigation water quality on human norovirus surrogate survival during leafy green production.

Introduction: The impact of water quality on the survival of human norovirus (NoV) was determined in irrigation water field run-off (tail water) and well water from a representative Central Coast vegetable production site in the Salinas Valley, California. Methods: Tail water, well water, and ultrapure water samples were inoculated separately with two surrogate viruses for human NoV-Tulane virus (TV) and murine norovirus (MNV)-to achieve a titer of 1×105 plaque forming units (PFU)/ml. Samples were stored at 11, 19, and 24°C for 28 days. Additionally, inoculated water was applied to soil collected from a vegetable production site in the Salinas Valley or to the surface of growing romaine lettuce leaves, and virus infectivity was evaluated for 28 days in a growth chamber. Results: Virus survival was similar for water stored at 11, 19, and 24°C and there was no difference in infectivity based on water quality. After 28 days, a maximum 1.5 log reduction was observed for both TV and MNV. TV decreased by 1.97-2.26 log and MNV decreased by 1.28- 1.48 logs after 28 days in soil; infectivity was not influenced by water type. Infectious TV and MNV were recovered from lettuce surfaces for up to 7 and 10 days after inoculation, respectively. Across the experiments there was no significant impact of water quality on the stability of the human NoV surrogates. Discussion: Overall, the human NoV surrogates were highly stable in water with a less than 1.5 log reduction over 28 days and no difference observed based on the water quality. In soil, the titer of TV declined by approximately 2 logs over 28 days, while MNV declined by 1 log during the same time interval, suggesting surrogate-specific inactivation dynamics in the soil tested in this study. A 5-log reduction in MNV (day 10 post inoculation) and TV (day 14 post inoculation) was observed on lettuce leaves, and the inactivation kinetics were not significantly impacted by the quality of water used. These results suggest that human NoV would be highly stable in water, and the quality of the water (e.g., nutrient content, salinity, and turbidity) does not significantly impact viral infectivity.

Presence of hepatitis E virus in commercially available pork products.

An increasing number of hepatitis E virus (HEV) infections in industrialized countries have been foodborne and linked to the consumption of undercooked pork products. To date, data on the prevalence of HEV in pork products sold in the United States is limited and no standard processing method exists for the detection of HEV in foods. In order to develop a processing method for the detection of HEV in pork products, ground pork and pork liver were selected for method development. Murine norovirus (MNV) was used as a process control. A filtration step prior to RNA detection was shown to reduce the level of PCR inhibitors in ground pork and an additional ultracentrifugation process was successful in removing PCR inhibitors in pork liver. MNV RNA was detected in ground pork and liver samples inoculated with 4.7 log10 PFU/g and 3.0 log10 PFU/g, respectively. Using the developed method for viral RNA detection in ground pork and pork liver, 20 packages of ground pork (six 1 g sub-samples per package) and 14 pork livers (four 1 g sub-samples per liver) were screened for the presence of HEV RNA. Fifteen out of 119 (12.6%) ground pork samples tested positive for HEV RNA and 13 out of 20 packages (65%) contained at least one positive sample. Twenty-five of 56 (45%) of pork liver samples were positive for HEV RNA and 6 of 14 livers (43%) had all sub-samples test positive for HEV RNA. Overall, the results indicate ground pork and pig liver as a potential source of HEV.

Redução da cristalização em doce de leite com a utilização da enzima ß Galactosidase / Reduction of crystallization in dulce de leche with the use of the enzyme beta Galactosidase

O mercado de produtos com baixo teor de lactose ainda é pouco explorado no Brasil, porém muitas pessoas sofrem de intolerância à lactose e muitos produtos lácteos cristalizam-se com maior facilidade devido à baixa solubilidade desse dissacarídeo. A hidrólise da lactose é um processo promissor para a indústria de alimentos porque possibilita o desenvolvimento de novos produtos sem lactose em suas composições. Esta operação oferece certas vantagens uma vez que ela diminui os riscos de cristalização em derivados lácteos e aumenta o poder adoçante. O objetivo deste trabalho foi fazer uma revisão de como utilizar a enzima ß – galactosidase no processo de redução do teor de lactose do leite a ser utilizado para a produção de doce de leite, aumentando o seu tempo de armazenamento, através da redução da arenosidade causada pela cristalização da lactose no processo de concentração.

Viabilidade da utilização de queijo tipo ricota na elaboração de pão de queijo / Viability of using ricotta in preparation of cheese bread

O pão de queijo é um produto genuinamente brasileiro, surgido em época indefinida nas fazendas de Minas Gerais, tendo como matéria-prima básica o polvilho azedo ou doce. Atualmente vem se destacando pelo consumo e pela produção nacional, chegando aos dias atuais até mesmo ao mercado internacional. Apesar de sua aceitação, o pão de queijo ainda não possui um padrão de qualidade e tecnologia de produção definidos devido à grande variedade de ingredientes opcionais. Diversas formulações são comercializadas e identificadas como "pão de queijo". O objetivo deste trabalho foi analisar a viabilidade da utilização de queijo tipo ricota na elaboração de pão de queijo. Foram realizadas análises físicas de densidade, espessura da crosta, coeficiente de expansão, cor, textura e análise sensorial. As porcentagens de queijo utilizadas nas formulações foi 30 por cento para o queijo meia cura e 30, 40 e 50 por cento para o queijo tipo ricota, em relação à porcentagem de polvilho azedo. Em relação aos parâmetros analisados, conclui-se que o aumento da porcentagem de queijo tipo ricota na elaboração de pão de queijo tem como consequência um produto mais macio, com menor gomosidade, fracturabilidade, mastigabilidade e com uma espessura da crosta menor, não diferindo sensorialmente de pães de queijo elaborados com queijo minas meia cura. Conclui-se também que é viável produzir pão de queijo com a substituição total do queijo minas meia cura pelo queijo tipo ricota.

The cheese bread is a genuinely Brazilian product, which appeared in undefined time in the farms of Minas Gerais, with the basic raw material, cassava starch or sour cassava starch. Today has been highlighted by consumption and domestic production, up to today, even to the international market. Despite its acceptance, the cheese bread does not have a standard of quality and production technology defined by the great variety of optional ingredients. Several formulations are marketed and labeled as "cheese bread". The aim of this study was to analyze the feasibility of using ricotta cheese in the preparation of cheese. Physical analyzes density, crustal thickness, coefficient of expansion, color, texture and sensory. The percentages of cheese used in the formulations was 30 percent for half the cheese curing and 30 percent, 40 percent and 50 percent for the ricotta cheese, in relation to the percentage of cassava starch. The parameters analyzed it is concluded that increasing the percentage of ricotta cheese in the preparation of cheese bread has resulted in a softer, less gumminess, fracture, and chewiness of the crust with a thickness less, no difference in sensory cheese bread made with cheese half cure. It also follows that it is feasible to produce cheese bread with total replacement of the cheese half cure for ricotta cheese.