The rational use of lactobacilli and lysozyme (LZ) could be a simple strategy for boosting key enzyme activities during cheese ripening. This study investigated the effect of the application of LZ on the cell envelopes and metabolic potential of two strains of mesophilic lactobacilli: Lactiplantibacillus plantarum 29 (L29) and Lacticaseibacillus rhamnosus 77 (L77). An in vitro study of LZ-sensitivity was carried out on the two strains. In L29 (only), the results of turbidity, culturability and physiological profile as well as fluorescence microscopy images and scanning electron micrographs confirmed a high-level of sensitivity to LZ. Therefore, L29 alone or in combination with LZ as well as a cell-free extract of L29 were used as ripening agents in the manufacture of a mature cheese. The release of peptidases in the cheese matrix by the lysis of L29 in situ was validated and associated with positive effects on the cheese quality, especially the increase of hydrophilic peptide levels.

The purpose of this paper is to understand the milk processing system practiced in the Mongolian nomadic Khalkha groups of Su'qbaatar and Dornod Provinces in eastern Mongolia through a field survey, to compare it with surrounding areas of Qentiy and Dundgowi Provinces, and then to analyze the transmission of processing techniques by further comparison with those of Syria, Jordan, Iran and Iraq in West Asia. The milk processing techniques of fermentation, cream separation and additive coagulation are all used in Su'qbaatar and Dornod Provinces. In fermentation processes, the technique of alcohol fermentation with churning is mainly used for cow milk to process alcoholic sour milk, followed by further processing to spirit, butter oil and non-matured dry cheese. In cream separation processes, the technique of heating/cream separation is used, in which cream is first separated from milk and non-matured dry cheese is processed from skim milk. In additive coagulation processes, the technique of fermented milk coagulation which utilizes lactic acid fermented whey as a coagulant is used to process non-matured dry cheese. These techniques are widely shared in the eastern part of Mongolia. It is characteristic of Su'qbaatar Province that the processing of cow milk is dominated by the technique of fermentation processes, mainly alcohol fermentation with churning. It is presumed that the technique of churning sour milk transmitted from West Asia to eastern Mongolia, and then the function of churning originally for butter processing was converted to allow for alcohol fermentation under the cooler environment in North Asia.

This study aimed to review hazard analysis and critical control points (HACCP) in the dairy industry for the production of yogurt. The food safety management system (FSMS) was implemented over the last several decades with several amendments. The need for practical and proactive procedures in the dairy industry was identified so that HACCP implementation could ensure that consumers would always have safe food. The concept of HACCP is a systemic and science-based method that can result in safe dairy products such as yogurt based on the complete analysis of manufacturing processes, recognition of hazards potentially present at all stages of production, and risk prevention. In yogurt production, raw milk receipt, pasteurization, packaging, and storage are the steps most susceptible to contamination and were considered critical control points. Further steps also need to be implemented to achieve other related control measures, and these will be discussed.

This research paper presents the characterization of an enterocin-producing Enterococcus durans MF5 isolate and the determination of the in vitro antilisterial activity of enterocin produced by this isolate, named Ent-MF5. PCR-based screening for bacteriocin biosynthetic genes revealed that E. durans MF5 harbors multiple enterocin-encoding genes (ent A, B, P and X), classified as class II bacteriocins and enterocin-P of Enterococcus faecium (sharing up to 99% similarity at the genetic level). E. durans MF5 is sensitive to eight clinically important antibiotics and does not possess cytolysin activator -cylA, gelatinase -gelE and hyaluronidase -hylA virulence genes. The antilisterial activity of Ent-MF5 was abolished by trypsin, α-chymotrypsin, protease and proteinase-K. Ent-MF5 showed thermal and pH stability. In addition, the activity of Ent-MF5 was unaffected in the presence of various surfactants (1% SDS, Triton X-100, Tween 20, and Tween 80). Ent-MF5 exhibited antimicrobial activity against Listeria monocytogenes, Listeria innocua, Listeria ivanovii and Listeria seeligeri at concentrations as low as 0.13 μg/ml. Ent-MF5 had a bactericidal effect against L. monocytogenes with a significant reduction in surviving cells at concentrations equal to or greater than 0.13 μg/ml. A 75–100% reduction in L. monocytogenes growth and bactericidal effect determined by CFU counts was observed following treatment with Ent-MF5 at 4.47 μg/ml at time points starting at 2 and 4 h, respectively. Ent-MF5 action is associated with Listeria cell membrane damage, as observed by flow cytometry and fluorescence microscopy. Thus, the effective antilisterial activity and stability of Ent-MF5 presents promising perspectives for application as biopreservatives in the food industry.