Barzideh Zoha, Siddiqi Myra, Mohamed Hassan Mahmoud, LaPointe Gisèle
Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada.
Faculty of Computer and Artificial Intelligence, Benha University, Banha 13518, Egypt.
Microorganisms. 2022 Aug 19;10(8):1669. doi: 10.3390/microorganisms10081669.
The microbial community of industrially produced Canadian Cheddar cheese was examined from curd to ripened cheese at 30-32 months using a combination of viable plate counts of SLAB (GM17) and NSLAB (MRSv), qPCR and 16S rRNA gene amplicon sequencing. Cell treatment with propidium monoazide excluded DNA of permeable cells from amplification. The proportion of permeable cells of both spp. and spp. was highest at 3-6 months. While most remaining spp. cells were intact during later ripening stages, a consistent population of permeable spp. cells was maintained over the 32-month period. While sequence variants were significant biomarkers for viable cheese curd communities at 0-1 m, was identified as a distinctive biomarker for cheeses from 7 to 20 months. From 24 to 32 months, was replaced in significance by four genera ( and at 24 m and at 30-32 m, and ). These results underscore the importance of monitoring potential defects in cheeses aged over 24 months, which could be diagnosed early through microbial DNA profiling to minimize potential waste of product. Future perspectives include correlating volatile flavor compounds with microbial community composition as well as the investigation of intra-species diversity.
采用平板活菌计数法（用于嗜温乳酸菌，GM17培养基；用于非嗜温乳酸菌，MRSv培养基）、定量聚合酶链反应（qPCR）和16S rRNA基因扩增子测序相结合的方法，对工业化生产的加拿大切达干酪从凝乳到30 - 32个月成熟奶酪的微生物群落进行了检测。用单叠氮化丙锭处理细胞可排除可渗透细胞的DNA进行扩增。嗜温乳酸菌属和非嗜温乳酸菌属的可渗透细胞比例在3 - 6个月时最高。在后期成熟阶段，大多数剩余的嗜温乳酸菌属细胞保持完整，而在32个月的时间里，可渗透的非嗜温乳酸菌属细胞数量保持稳定。虽然在0 - 1个月时，嗜温乳酸菌属序列变异体是活奶酪凝乳群落的重要生物标志物，但在7至20个月的奶酪中，嗜热栖热放线菌被确定为独特的生物标志物。在24至32个月时，嗜热栖热放线菌的重要性被四个属（24个月时的嗜热栖热放线菌属和嗜热栖热放线菌属，30 - 32个月时的嗜热栖热放线菌属和嗜热栖热放线菌属）所取代。这些结果强调了监测24个月以上陈年奶酪潜在缺陷的重要性，通过微生物DNA分析可以早期诊断这些缺陷，以尽量减少产品的潜在浪费。未来的研究方向包括将挥发性风味化合物与微生物群落组成相关联，以及研究种内多样性。
