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We monitored the production process of Xinjiang dry‐cured mutton ham, and recorded changes in physicochemical and sensory quality such as appearance, texture, and aroma using E‐nose, texture profile analysis (TPA), and gas chromatography‐mass spectrometer (GC‐MS). During dry‐cured mutton ham processing, the moisture content decreased from 76% to 34%, while the NaCl content increased from 0.18% to 9.85%. Lipid oxidation was observed throughout the processing of dry‐cured mutton ham. Moreover, the nitrite content rapidly declined and reaching a minimum value of 1.58 mg/kg. During processing, the hardness of ham increased and its texture becomes tight, the chewability and gumminess improved over time. The muscle appeared rosy red, and the surface fat gradually became yellowish. Notably, seven classes of volatile compounds were identified among which aldehydes were the highest. Correlation analysis revealed that unsaturated fatty acids have a significant contribution to the composition of volatile compounds. PCA and cluster analysis results showed that the separation trend of the overall aroma profile of the dry‐cured mutton ham is obvious at different processing times. The quality of dry‐cured mutton ham changed the most during fermentation which was the key process stage of quality stabilization and improvement in the processing of dry‐cured mutton ham. These results provide information regarding the changes in aroma and quality of dry‐cured mutton ham during processing and are important for promoting the industrial processing of dry‐cured mutton ham. Practical applications: This study monitored the quality changes during the production of Xinjiang dry‐cured mutton ham. These results provide a basis for improving the quality of dry‐cured mutton ham and are important for promoting the industrial production of dry‐cured mutton ham. Developing high‐quality dry‐cured mutton ham will have a positive effect on promoting the added value of the mutton processing industry. [ABSTRACT FROM AUTHOR]

Thyme essential oil (TEO) and sausage diameter effects on biogenic amines (BA) formation and microbial communities in traditional Xinjiang smoked horse meat sausage were studied. Evaluation of the pH, moisture content, and microorganisms population of smoked horsemeat sausage was done. Significant differences due to sausage size were found for BA and microbial populations. Smaller diameter sausages showed decreased (P < 0.05) BA compared to the larger diameter sausages. The use of TEO greatly reduced BA (tyramine, putrescine, cadaverine, and histamine). In addition, TEO decreased the total bacterial count and more specifically the Gram-negative Enterobacteriaceae family (P < 0.05). High throughput sequencing showed that essential oil (EO) treatment and the difference in sausage diameter did not change the predominant microbiota in sausages during fermentation. However, the relative abundance of the microbiota can be changed. The correlation heat map showed relationships between the microbial community and BA production. Staphylococcus , Leuconostoc, and Lactobacillus showed a strong positive relationship with BA formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effects of NSLAB on Kazakh cheese ripening was studied. • Cheeses made using P. acidilactici , S. epidermidis , and L. rhamnosus were prepared. • NSLAB cheeses had different protein contents, free fatty acid contents, and pH. • NSLAB cheeses had different flavor compounds and odor profiles (volatile components). • NSLAB can be used as an adjunct starter to make Kazakh cheese. Xinjiang is a multiethnic region of China. Traditionally, most ethnic minorities are known to produce and consume cheese. Nomadic people have been reported to use lactic acid bacteria (LAB) for decades to produce fermented dairy products as part of a balanced diet. Non-starter LAB (NSLAB) contribute to different degrees of ripening, depending on the cheese variety. In the present study, we screened three types of NSLAB with good proteolysis and autolytic abilities from traditional Kazakh cheese: Pediococcus acidilactici R3-5, Staphylococcus epidermidis R4-2, and Lactobacillus rhamnosus R9-6. A control (no NSLAB) was also included, resulting in four distinct types of cheese samples. We used gas chromatography-mass spectrometry and the electronic nose system to identify volatile compounds and analyze the effect of NSLAB on cheese flavor at the ripening stage. The physicochemical indicators changed significantly during the ripening of Kazakh cheese. Compared with the control, the protein content, free fatty acid content, pH, flavor compounds, and odor profiles of the test cheeses were significantly different. The major chemical differences among cheeses were the synthesis of some key volatile components (ethyl caprylate, ethyl caprate, myristyl carbonate, capric acid, caprylic acid, nonanal, and benzyl alcohol). NSLAB can be used as an adjunct starter to make Kazakh cheese and the use of NSLAB affected the cheese flavor quality positively. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus (S. aureus) is a common pathogen found in dairy products whose enterotoxins are the main pathogenic factors that cause food poisoning. In this study, a total of 399 samples of retail Kazak cheese collected from 4 regions in Xinjiang (China) were qualitatively and quantitatively analyzed for the presence of bacteria. Among them, 56 (14%, 95% CI: 10.6–17.4%) samples were found to be positive for S. aureus , and their distribution and degree of contamination vary from region to region, with 19.4% (31/160) in Altay, 10.7% (23/215) in Yining and 22.2% (2/9) in Tacheng, and corresponding geometric mean level of 5.8, 4 and 3 most probable number/gram, respectively. In addition, 62 strains of S. aureus were isolated from the positive samples. The most frequently detected gene in the 3 regions was staphylococcal enterotoxin gene c (sec) (29%), followed by sea (25.6%), see (9.8%), sed (8%), seb (3.2%). Finally, the analysis of 13 resistance genes and the minimum inhibitory concentration (MIC) of 12 antibiotics in 62 strains of S. aureus identified 13 methicillin-resistant S. aureus strains (21%). The S. aureus isolates showed most resistance to penicillin (69.3%), followed by erythromycin (27.4%) and clindamycin (24.2%). There were 17 (27.4%) strains of S. aureus with multiple drug resistance, and one strain was even resistant to 10 antibiotics. A high frequency of bla Z (45.2%) and mec A (16.1%) resistance genes was found among the S. aureus isolates. Among the penicillin-resistant strains, 60.5% (26/43) had the bl aZ gene. The findings of this study suggest that S. aureus has spread across different regions of Xinjiang. The presence of S. aureus strains in Kazak cheese during the selling period poses a potential threat to public health and underscores the need for the continuous monitoring of these cheeses. • The comprehensive study on Staphylococcus aureus isolated from retail artisanal Kazak cheese in Xinjiang, China. • High prevalence of S. aureus in Kazak cheese. • S. aureus strains exhibited multiple drugs and carried various enterotoxin and antimicrobial resistance genes. • S. aureus strains are opportunistic pathogens, which are potential safety hazards for consumers. • S. aureus may spread among different regions in Xinjiang. [ABSTRACT FROM AUTHOR]