4/2/2023 0 Comments Virtual chemlab v4.5In order to obtain this seal, it is not enough for the cheese to be produced by a certified cheese maker according to PDO specifications each batch of cheese is indeed also subjected to sensory testing by a trained panel from an independent certifying body (Confraria do Queijo de São Jorge). However, the variability of the final product-expected in view of its being manufactured from raw milk, is often sufficient to compromise the PDO seal. Therefore, the indigenous microbiota of the raw milk and the starter culture (NWS) is important for the subsequent ripening process, as both actively contribute to the characteristic aroma and spicy flavor of the final product. By the end of the ripening, São Jorge cheese has small, irregular eyes, and its flavor is characterized by strong, clean and slightly spicy notes that become more intense as it matures. This is followed by the ripening process, which lasts at least 3–4 months. Acidification takes place at 30 ☌ and is followed by cooking the curd at 35–36 ☌, draining the whey, shaping the curd, and salting and pressing the curd. It is produced from raw cow’s milk to which a natural whey starter (NWS) is added, obtained from the whey of the previous day’s cheese-making. This cheese exhibits a yellowish, hard or semi-hard paste and a crumbly texture. It bears major economic and social importance on the island. São Jorge cheese is a very popular Portuguese cheese produced from raw cow’s milk on the island of São Jorge in the Azores. The characterization of the NWS and the cheese microbiota can contribute to a better understanding of the microbial dynamics of this traditional PDO cheese and can help producers interested in maintaining the identity and quality of São Jorge PDO cheese. This study has helped to clearly distinguish between cheeses with and without PDO based on the composition of the bacterial community. A reduction in contaminating bacteria was found to be crucial for the development of a bacterial community rich in Leuconostoc and Lactobacillus, thus justifying the PDO seal of quality. A negative correlation was found between contaminating bacteria, e.g., Staphylococcus and Acinetobacter, and the development of PDO-associated bacteria such as Leuconostoc, Lactobacillus and Enterococcus. Certified cheeses were richer in Leuconostoc, Lactobacillus and Enterococcus, but had fewer Streptococcus ( p < 0.05). Significant differences ( p < 0.05) in bacterial community composition were found between PDO cheese and non-certified cheese Leuconostoc was found to play the chief role in this regard. The NWS and curd microbiota was dominated by Streptococcus and Lactococcus, whereas Lactobacillus and Leuconostoc were also present in the core microbiota of the cheese along with these genera. The aim of this work was to characterize the bacterial diversity of this cheese using next-generation sequencing (NGS) and to identify the specific microbiota that contributes most to its uniqueness as a PDO by distinguishing the bacterial communities of PDO and non-PDO cheeses. Although it is produced according to Protected Designation of Origin (PDO) specifications, the granting of the PDO label depends crucially on sensory evaluation by trained tasters. São Jorge cheese is an iconic product of the Azores, produced from raw cow’s milk and natural whey starter (NWS).
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