The aim of the present study was to assess the efficacy ofmultiplex PCR in detecting the adulterationof commercially available ground beefvia addition and/orsubstitution ofground buffalo meat. Experimentally adulterated ground beefsamples were prepared in triplicate, and dilutions of DNA from Bos taurus and Bubalusbubalis were prepared to determine the detection limit of the method. Concurrently, 91 ground meatsamples sold as “ground beef” were collected from differentstores in northern Brazil andanalyzed bymultiplex PCR. Buffalo DNA was detected in 17.5% of the collected ground meat samples.Our results showed that multiplex PCR is an efficient method for detectingthe incorporation of groundbuffalo meatatpercentages ranging from 10 to 100% and the incorporation of beef at percentages ranging from0.1 to 100% intoground meat samples.

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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.