PDF(Pubmed)
Abstract：
Using whey, a by-product of the cheese-making process, is important for maximizing resource efficiency and promoting sustainable practices in the food industry. Reusing whey can help minimize environmental impact and produce bio-preservatives for foods with high bacterial loads, such as Mexican-style fresh cheeses. This research aims to evaluate the antimicrobial and physicochemical effect of CFS from Lactobacillus casei 21/1 produced in a conventional culture medium (MRS broth) and another medium using whey (WB medium) when applied in Mexican-style fresh cheese inoculated with several indicator bacteria (Escherichia coli, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Listeria monocytogenes). The CFSs (MRS or WB) were characterized for organic acids concentration, pH, and titratable acidity. By surface spreading, CFSs were tested on indicator bacteria inoculated in fresh cheese. Microbial counts were performed on inoculated cheeses during and after seven days of storage at 4 ± 1.0 °C. Moreover, pH and color were determined in cheeses with CFS treatment. Lactic and acetic acid were identified as the primary antimicrobial metabolites produced by the Lb. casei 21/1 fermentation in the food application. A longer storage time (7 days) led to significant reductions (p < 0.05) in the microbial population of the indicator bacteria inoculated in the cheese when it was treated with the CFSs (MRS or WB). S. enterica serovar Typhimurium was the most sensitive bacteria, decreasing 1.60 ± 0.04 log10 CFU/g with MRS-CFS, whereas WB-CFS reduced the microbial population of L. monocytogenes to 1.67 log10 CFU/g. E. coli and S. aureus were the most resistant at the end of storage. The cheese\'s pH with CFSs (MRS or WB) showed a significant reduction (p < 0.05) after CFS treatment, while the application of WB-CFS did not show greater differences in color (ΔE) compared with MRS-CFS. This study highlights the potential of CFS from Lb. casei 21/1 in the WB medium as an ecological bio-preservative for Mexican-style fresh cheese, aligning with the objectives of sustainable food production and guaranteeing food safety.
摘要：
用乳清,奶酪制作过程中的副产品，对于最大限度地提高资源效率和促进食品工业的可持续做法非常重要。重复使用乳清可以帮助最大限度地减少对环境的影响，并为高细菌含量的食品生产生物防腐剂。比如墨西哥风格的新鲜奶酪。这项研究旨在评估在常规培养基（MRS肉汤）和使用乳清的另一种培养基（WB培养基）中生产的干酪乳杆菌21/1的CFS的抗菌和物理化学作用，当将其应用于接种了几种指示细菌的墨西哥风格新鲜奶酪（大肠杆菌，伤寒沙门氏菌，金黄色葡萄球菌,和单核细胞增生李斯特菌)。CFS(MRS或WB)的有机酸浓度进行了表征，pH值,和可滴定的酸度。通过表面扩散，在新鲜奶酪中接种的指示细菌上测试CFS。在4±1.0°C下储存七天期间和之后，对接种的奶酪进行微生物计数。此外，用CFS处理测定干酪中的pH和颜色。乳酸和乙酸被鉴定为由Lb产生的主要抗微生物代谢物。干酪21/1发酵在食品中的应用。当用CFS(MRS或WB)处理干酪时,较长的储存时间(7天)导致接种在干酪中的指示细菌的微生物群体显著减少(p<0.05)。肠球菌伤寒菌是最敏感的细菌，用MRS-CFS降低1.60±0.04log10CFU/g，而WB-CFS将单核细胞增生李斯特菌的微生物种群减少到1.67log10CFU/g。大肠杆菌和金黄色葡萄球菌在储存结束时抗性最强。用CFSs（MRS或WB）处理后，奶酪的pH值显著降低（p<0.05），与MRS-CFS相比，WB-CFS的应用并未显示出更大的颜色差异（ΔE）。这项研究强调了Lb的CFS的潜力。casei21/1在WB培养基中作为墨西哥风格新鲜奶酪的生态生物防腐剂，与可持续粮食生产和保障食品安全的目标保持一致。
