Vargashald9267

Overall, this study provided a comprehensive description of the dynamic changes of physicochemical parameters, flavor compounds, and microbiota profiles throughout the natural production of plain sufu. The similarities and variations among different stages, as well as correlation between flavor compounds and microbiotas would help to understand the mechanism of plain sufu production, and further to enhance the quality control of plain sufu. Inadequate cooking during sous-vide processing may cause foodborne diseases in case the food is contaminated with pathogens such as Listeria monocytogenes. In this study, thermal inactivation of L. monocytogenes in sous-vide processed salmon was investigated. Oregano oil and citric acid were used alone or in combination to determine the probability of increasing the efficiency of heat treatment. Control (C); 0.5% citric acid added (S); 1% oregano essential oil added (O); and citric acid and oregano essential oil combined (OS) groups were prepared. Samples were inoculated with L. monocytogenes, vacuum packed, then sous-vide cooked at 55, 57.5, 60, or 62.5 °C for predetermined times. The D-values of all treated samples were significantly lower than control. The use of oregano oil (O), citric acid (S) and their combination (OS) significantly reduced the time required to inactivate L. monocytogenes. read more The z-values of L. monocytogenes in C, O, S and OS groups were 5.50, 5.62, 6.54, and 6.92 °C, respectively. It was determined that effective results could be achieved by adding natural antimicrobials to provide safety in sous-vide fish. Artisanal cheese from southern Chile is made primarily by rural families who raise dairy cows and produce cheese as a way to add value to their milk. The most common cheese produced is chanco, a semi-hard cheese that is typically sold in unauthorized markets. The methods of chanco production do not always follow good manufacturing practices; however, the presence of Listeria monocytogenes contamination in this cheese has not been previously documented. To better understand production practices and L. monocytogenes contamination, 39 cheese producers were surveyed with regard to infrastructure, cleaning and sanitation, pest control, personal hygiene, training, raw materials, and manufacturing. During four sampling trips in 2016 (March, May, August, and November), 546 samples were collected (468 cheese samples and 78 milk samples). For producers that tested positive for L. monocytogenes, environmental monitoring was also conducted, for which 130 additional samples were collected. Presumptive L. monocytogenes iso of southern Chile. Fumonisins contamination of food commodities is a worldwide problem, especially for maize. The ability to produce fumonisinsis a trait of several species of Fusarium, mainly F. verticillioides and F. proliferatum on maize, and some Aspergillus species. A. niger and its sister species A. welwitschiae, can contribute to fumonisin B2 (FB2) accumulation in maize kernels, although to a lesser extent than fumonisin-producing Fusarium species. Fumonisins risk monitoring represents an effective strategy in the integrated approach for mycotoxin risk management and reduction. The availability of a user-friendlymolecular assay for the detection oftoxigenic fungal species represents a valuable tool in understanding and managing upcoming mycotoxin contamination. In this study, we developed a LAMP assay, based on the detection of fum10, for a rapid and specific molecular detection of FB2-producing A. niger and A. welwistchiae, potentially useful to perform monitoring directly "on site" in maize chain. Results showed that very low amounts of conidia are suitable to detect the presence of the target gene, thus providing information about the presence of FB2-producing Aspergillus species and the possible upcoming fumonisins contamination in maize. The assay was combined with a suitable protocol for "in field" crude DNA extraction and a colorimetric method for easy naked-eye evaluationof results, offering a reliable and user-friendly tool to support effective reduction strategies of mycotoxin contamination in crop management programs. The application of Campylobacter specific bacteriophages appears as a promising food safety tool for the biocontrol of this pathogen in the poultry meat production chain. However, their isolation is a complicated challenge since their occurrence appears to be low. This work assessed the efficiency of seven protocols for recovering Campylobacter phages from chicken skin samples inoculated at phage loads from 5.0 × 101 to 5.0 × 106 PFU/g. The enrichment of chicken skin in selective Bolton broth containing target isolates was the most efficient procedure, showing a low detection limit of 5.0 × 101 PFU/g and high recovery rates of up to 560%. This method's effectiveness increased as phage concentration decreased, showing its suitability for phage isolation. When this method was applied to isolate new Campylobacter phages from retail chicken skin, a total of 280 phages were recovered achieving an isolation success rate of 257%. From the 109 samples 68 resulted phage positive (62%). Chicken skin could be, therefore, considered a rich source in Campylobacter phages. This method is a simple, reproducible and efficient approach for the successful isolation of both group II and III Campylobacter specific bacteriophages, which could be helpful for the enhancement of food safety by reducing this pathogen contamination in broiler meat. The Glutamate Decarboxylase (GAD) system is important for survival of L. monocytogenes and other microorganisms under acidic conditions. Environmental conditions influence the function of the GAD system. Until now, the only conditions known to lead to increased transcription of the GAD system are the stationary phase in rich media and anoxic conditions. Previously, we showed that transcription of the GAD system requires unidentified compounds other than glutamate present in rich media. Following a test looking at various compounds we identified for first time that peptone, tryptone and casamino acids activate the GAD system under oxic conditions suggesting that amino acid(s) other than glutamate and/or peptides are important for the above process. The defined medium, where the GAD system is inactive, once it is supplemented with the above compounds results in an active intracellular and extracellular GAD system and increased acid resistance. Through functional genomics we show that these compounds are required for GadD2 activity and although we previously showed that GadD3 is active part of the intracellular GAD system, the supplementation did not activate this gene.