Nesta pesquisa teve-se como objetivo o desenvolvimento de uma bebida láctea fermentada à base de soro de queijo mussarela e polpa de umbu. Foram avaliadas as características físico-químicas e físicas a aceitação sensorial, além do efeito da temperatura e da concentração de soro sobre a massa específica das bebidas que foram formuladas variando-se, somente, a concentração de soro (20%, 40%, 60% e 80%). A partir dos resultados obtidos e das análises estatísticas verificou-se que os valores para as características físico-químicas e aceitação sensorial não apresentaram diferença significativa entre os tratamentos 20%, 40% e 60% (P > 0,05). A partir dos resultados obtidos das análises físico-químicas e sensorial pode-se concluir que a melhor bebida foi aquela que apresentou concentração de soro de 60%, devido a utilização de maior quantidade de soro. Para a análise da influência da concentração de soro e temperatura sobre a massa específica foi ajustado um modelo linear múltiplo sem interação dos parâmetros, com coeficiente de determinação satisfatório. Palavras-chave: densidade, calor específico, resíduo, aceitação sensorial. ELABORATION AND CHARACTERIZATION OF A DAIRY FERMENTED DRINK PRODUCED WITH UMBU (Spondias tuberosa sp.

View related articles View Crossmark data Citing articles: 1 View citing articles Application of a multiplex polymerase chain reaction (mPCR) assay to detect fraud by substitution of bovine meat cuts with water buffalo meat in Northern Brazil

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Chagas disease, caused by the protozoan Trypanosoma cruzi, has often been linked to oral transmission through açai consumption. Molecular methods that allow fast and accurate identification of the pathogen are important for the detection of the presence of the parasite in this food. This study aimed to optimize polymerase chain reaction (PCR)-based detection of T. cruzi DNA in açai pulp. Several dilutions of T. cruzi DTU TcI trypomastigote forms were cultured in liver infusion tryptose (LIT) medium. Trypanosoma cruzi DNA was extracted from the cells and subjected to PCR. Subsequently, culture dilutions were added to açai pulp to evaluate the detection threshold of the optimized PCR assay. We demonstrate that our assay can detect T. cruzi DNA in açai pulp at a concentration of 1.08 × 10-10 ng µL-1. We conclude that our optimized protocol is effective and can be used as an important tool for the detection of T. cruzi contamination in açaí.

The seasons influence the production of buffalos' milk. Because of this, the producers may produce a mixture of buffalo and bovine milk during cheese production in periods of low production. Therefore, the present work aimed to investigate fraud in buffalo cheese and the relationship between seasonality and different physicochemical properties of buffalo cheeses produced and marketed in eastern Amazonia. We obtained commercial samples of buffalo cheese during two Amazonian climatic periods from commercial points of Marajó-Pará, Brazil. After collection, there were lipid, protein, ash, and humidity analyses. Determination of carbohydrates and energy values was also performed for the nutritional characterization of samples, as well as for mPCR analysis to detect buffalo and/or bovine DNA. DNA extraction protocol of the samples was standardized and two pairs were used for the mPCR reaction, amplifying fragments of approximately 220 bp for Bubalus bubalis DNA and 346 bp fragments for Bos taurus DNA. Among the samples acquired in the rainy season, we observed that 33% were inadequately labeled, indicating fraud from cow's milk incorporation and fraud from substitution of raw material. From the nine samples obtained in the dry season, all the samples showed cow's milk incorporation fraud. The highest fraud rate coincided with the period of low milk production from buffalo and there was a difference in composition between fraudulent and non-fraudulent cheeses. Therefore, seasonality influences increase in cattle milk for the production of buffalo cheese, and this adulteration may decrease the nutritional content of the product.

This study aimed to perform a comparative validation of the efficiency of quantitative SYBR Green qPCR and simplex PCR identification of Salmonella spp. DNA. For this, the samples of DNA from the Salmonella typhimurium were diluted up to 10-5 in duplicate. The results showed that the same primers were effective for both simplex PCR and qPCR. It was possible to detect the bovine species up to a dilution of 10-1 using simplex PCR. For all dilutions, it was possible to obtain qPCR amplification with a minimum Ct value of 15.13 for the 10-1 dilution for Salmonella spp. Next, the SYBR Green qPCR amplicons were separated using agarose gel electrophoresis for confirmation of the amplified fragment size. The superiority of qPCR over multiplex PCR was validated in terms of sensitivity, even with the use of SYBR Green dye, suggesting the possible use for quality control in foodstuffs.

Microbiological safety of fish is a concern of consumers, industries and regulatory agencies worldwide. Among the pathogenic microorganisms, Salmonella spp. is one of the main agents of foodborne diseases and should be absent in animal products. Rapid and accurate identification of pathogens in the supply chain is important for both quality assurance and tracking infectious agents within the chain. In this context, this study aimed to evaluate the equivalence of two rapid detection tests, as alternative methods to the conventional Salmonella detection method, as well as to verify the microbiological quality parameters of two commercially important fish species in the Amazon biome. The plate count of aerobic bacteria ranged from 7.76 x 10 4 to 8.71 x 10 7 CFU.g-1 for mesophiles and 1.70 x 10 6 to 4.27 x 10 8 CFU.g-1 for psychrotrophic whereas the maximum for this group of microorganisms in fresh fish is 10 6 CFU.g-1. Regarding the Staphylococcus count, the two species presented variations between 1.35 x 10 4 to 1.51 x 10 5 CFU.g-1. This represents unsatisfactory conditions of handling, storage and conservation of fish species. The immunoenzymatic and molecular methods have been shown to be reliable, fast and effective in the detection of Salmonella and for its high index of agreement with the conventional detection method. We also emphasize the convenience of multiplex PCR application due to the high sensitivity, specificity, speed and accuracy of Salmonella detection.

The objective of the present study was to Standardize a Polymerase Chain Reaction (PCR) protocol for the authentication of bovine and buffalo milk, and to detect the presence of Salmonella spp. and Listeria monocytogenes. For this, the target DNA was extracted, mixed, and subjected to a PCR assay. Milk samples were defrauded and experimentally contaminated with microorganisms to assess the detection of target DNA at different times of cultivation, bacterial titers, and concentration of genetic material. In addition, the protocol was tested with DNA extracted directly from food, without a pre-enrichment step. The proposed quadruplex PCR showed good accuracy in identifying target DNA sequences. It was possible to simultaneously identify all DNA sequences at the time of inoculation (0h), when the samples were contaminated with 2 CFU/250mL and with 6h of culture when the initial inoculum was 1 CFU/250mL. It was also possible to directly detect DNA sequences from the food when it was inoculated with 3 CFU/mL bacteria. Thus, the proposed methodology showed satisfactory performance, optimization of the analysis time, and a potential for the detection of microorganisms at low titers, which can be used for the detection of fraud and contamination.