Microbial Populations of Fresh and Cold Stored Donkey Milk by High-Throughput Sequencing Provide Indication for A Correct Management of This High-Value Product

Microbiological Quality of Raw Donkey Milk from Serbia and Its Antibacterial Properties at Pre-Cooling Temperature

The aim of this study was to examine the microbiological quality of raw donkey milk of an indigenous Serbian breed as well as the changes in the microbial populations during storage at 4 °C. In addition, antibacterial activity of donkey milk against E. coli, L. monocytogenes and S. aureus at 15 °C as well as the content of the two main antibacterial proteins lysozyme and lactoferrin were investigated. Microbiological examination of 137 individual milk samples collected over a period of 21 months showed good microbiological quality since foodborne pathogens such as Salmonella spp. and L. monocytogenes were not detected in any of the analyzed samples, while the number of E. coli, Enterobacteriaceae, total coliform bacteria, sulfite-reducing Clostridia and aerobic sporogenic bacteria was below the limit of quantification (<1 cfu mL^-1). During the six-days storage at 4 °C, total bacterial counts and the counts of lactic acid bacteria remained at the initial level while pathogenic bacteria were not detected. The strongest antibacterial activity of the tested milk was observed against E. coli, while S. aureus was the least sensitive to milk antibacterial compounds. Although further research is needed to fully elucidate the antibacterial mechanism and synergistic activity of different compounds in donkey milk, the high content lysozyme (2.63 ± 0.03 g L^-1) and lactoferrin (15.48 mg L^-1) observed in tested milk could contribute to its strong antibacterial activity and extension of the storage period during which it can be safely consumed.

Processing, Characteristics and Composition of Umqombothi (a South African Traditional Beer)

Traditional beers, such as palm wine, kombucha and others, are notable beverages consumed all over the globe. Such beverages historically contribute to food security on a global scale. Umqombothi is a South African traditional beer nutritionally packed with minerals, amino acids, B-group vitamins and much-needed calories. As a result, the production and consumption of this traditional beverage has been an integral part of South African’s social, economic and cultural prosperity. Unfortunately, difficulties in bioprocessing operations have limited its availability to household and small-scale production. It is at these micro-production scales that poor hygiene practices and the use of hazardous additives and contaminated raw materials continue to increase, posing serious health risks to the unassuming consumer. This study provides an overview of the processing steps and underlying techniques involved in the production of umqombothi, while highlighting the challenges as well as future developments needed to further improve its quality and global competitiveness with other alcoholic products.

Snapshot of Cyprus Raw Goat Milk Bacterial Diversity via 16S rDNA High-Throughput Sequencing; Impact of Cold Storage Conditions

In general, it is a common practice among dairy producers to store the milk in the refrigerator directly after milking, in order to preserve it and prevent the development of spoilage microbes. However, the impact of keeping the milk in the refrigerator overnight on milk microbial diversity has been poorly investigated. This study aimed to provide a snapshot of the bacterial composition of goat milk after direct storage at −80 °C and after being kept overnight at 4 °C and then in storage at −80 °, using high-throughput sequencing (HTS). Goat milk samples from four different farms were analyzed, to reveal that milk bacterial diversity differed between the two different storage conditions. Goat milk directly stored at −80 °C was characterized by the presence of the Gram-negative contaminants Pseudomonas and Acinetobacter, in addition to the genera Corynebacterium, Chryseobacterium, Bacteroides and Clostridium. Milk samples that were kept overnight at 4 °C were characterized by a reduction in their bacterial biodiversity and the predominance of the Gram-negative, aerobic Phyllobacterium. Overall, HTS methodologies provide an in-depth identification and characterization of the goat raw milk microbiome. Further, they offer a better understanding of the contribution of cold storage conditions to milk microbiota formation. This study may assist dairy producers in improving raw milk and raw milk cheeses quality and guaranteeing consumers’ safety.

Compared analysis of microbial diversity in donkey milk from Xinjiang and Shandong of China through High-throughput sequencing

Donkey milk has received increasing attention from consumers and dairy industry because of its nutritional value, health benefits, and proximity to human milk. Microbial diversity in donkey milk has a great impact on its quality and safety, however, microbiota in donkey milk from the major donkey-breeding regions of China have not been well documented. In this study, bacterial communities in donkey milk from Yopurga County in Western China (XJ), and Dong'e County in Eastern China (SD) were determined using high-throughput sequencing. Major phyla identified in the two donkey milk groups consistently included Acinetobacter, Proteobacteria, Firmicutes, and Bacteroidetes but with very different abundance for each phylum. Prevelence of genera was found to be diverse between the two groups, with Macrococcus and Acinetobacter dominating in the XJ samples while Streptococcus, Pseudoclavibacter, and Pseudomonas being the most abundant ones in the XJ samples. Alpha diversity analysis showed that there was significant difference in richness between the two sample groups but no difference in bacterial community diversity or coverage. The presence of possible harmful bacteria and lactic acid bacteria in donkey milk in this study provides the microbial profiles of pathogens and spoilage bacteria that need to be controlled and proposes possible utilization of beneficial microbial resources for the future.