Analyses of physicochemical properties, bacterial microbiota, and lactic acid bacteria of fresh camel milk collected in Inner Mongolia

Abstract

Camel milk has significant economic value and is an important food in the region of Alxa Left Banner of Inner Mongolia. Fifteen fresh camel milk samples were collected from domesticated camels in a pasture of Alxa Left Banner. The physicochemical properties and bacterial diversity of camel milk samples were analyzed. The average values of fat, total protein, nonfat milk solids, acidity, and density were 4.40%, 3.87%, 9.50%, 16.95°T, and 1.02 g/cm 3 , respectively. The bacterial microbiota of the collected fresh camel milk was investigated using PacBio single-molecule real-time (Pacific Biosciences, Menlo Park, CA) sequencing. The camel milk microbiota was highly diverse and comprised 8,513 operational taxonomic units belonging to 32 phyla, 377 genera, and 652 species. The major phyla included Proteobacteria, Firmicutes, Deinococcus-Thermus, Bacteroidetes, and Actinobacteria. A small number of lactic acid bacteria sequences were detected, representing the species Streptococcus thermophilus, Lactobacillus helveticus, Lactococcus lactis, and Leuconostoc mesenteroides. A total of 72 strains of lactic acid bacteria were isolated and identified from 15 samples, including Lactobacillus paracasei, Enterococcus italicus, Enterococcus durans, Lactococcus lactis ssp. lactis, Weissella confusa, and Enterococcus faecium. These results confirm that fresh camel milk has a high bacterial diversity and is a valuable natural resource for isolation of novel lactic acid bacteria.

Functional and Genomic Characterization of Ligilactobacillus salivarius TUCO-L2 Isolated From Lama glama Milk: A Promising Immunobiotic Strain to Combat Infections

“…To the best of our knowledge, this is the first report describing the isolation of LAB from the milk of Lama glama. We showed that llama milk contains a population of LAB, including lactobacilli and cocci, similar to the milk of other camelids (Khedid et al, 2009;Dong et al, 2012;Rahmeh et al, 2019;Zhao et al, 2020). Studies of cultivable LAB from raw dromedary milk demonstrated the presence of L. lactis (17.5%), S. thermophilus (9.2%), and lactobacilli (20.8%) (Khedid et al, 2009) or E. faecium (20.7%), L. lactis (17.2%), and lactobacilli (12%) (Rahmeh et al, 2019).…”

“…Moreover, a study reported that the most abundant cultivable species of Gram-positive cocci included Enterococcus faecium and Lactococcus lactis; the most abundant lactobacilli species included Lactobacillus helveticus, Lacticaseibacillus casei (basonym: Lactobacillus casei (Zheng et al, 2020), and Lactiplantibacillus plantarum (basonym: Lactobacillus plantarum). Subsequent studies confirmed the dominance of enterococci and lactococci in the cultivable bacteria from camel milk but detected certain differences in the predominant species of lactobacilli (Elbanna et al, 2018;Rahmeh et al, 2019;Zhao et al, 2020) that included Lacticaseibacillus paracasei (basonym: Lactobacillus paracasei), Lacticaseibacillus rhamnosus (basonym: Lactobacillus rhamnosus), and Limosilactobacillus reuteri (basonym: Lactobacillus reuteri). In addition to the characterization of microbial populations, certain strains with beneficial effects have been isolated from the camel milk.…”

Compositional and Functional Comparisons of the Microbiota in the Colostrum and Mature Milk of Dairy Goats

“…Therefore, these phyla might play more critical roles in the microbial ecosystem of goat colostrum and mature milk than the other phyla. On the other hand, Zhao et al [ 38 ] identified that Proteobacteria , Firmicutes , Deinococcus-Thermus , Bacteroidetes , and Actinobacteria were the predominant phyla of camel milk. These results suggested that fresh milk contains high bacterial diversity and is a valuable natural source of various kinds of bacteria.…”

Effect of animal origin and farm altitude on some physicochemical properties and minerals of milk samples

“…As general the study of ; Legesse et al (2017) is comparable to the samples from the high altitude because the altitude of the study area of their study is 1803 meters above sea level. A Pakistani research (Zhao et al, 2020), studied buffalo, cow and goat milk samples with regard to their pH, conductivity, moisture%, TDS%, speci c gravity, calcium, potassium, and sodium. The ndings of the Pakistani study were to some extent similar to the ndings of this study with slight differences except for the conductivity (10.8 ± 2.07 Pakistani compared 6.93 ± 0.60 in low altitude of our study and 5.56 ± 0.15 at the high altitude), TDS% (12.9 ± 1.01 Pakistani study compared to 18.43 ± 0.25 at low altitude and 14.07 ± 6.43 at high altitude) and ash% (1.04 ± 0.13 Pakistani compared to 0.58 ± 0.15 at low altitude and 3.51 ± 0.65 at high altitude of our study).…”

“…The physicochemical properties of milk include the pH, conductivity, speci c gravity, ash and water and total solids (TDS) percentages, viscosity and the optical characteristics such as the refractive index and the optical activity. With regard to the chemical composition of milk, it is majorly composed of proteins, minerals, and vitamins (FAO, 2020;Zhao et al, 2020).…”