Strain HY-1, isolated from raw milk, was identified as Hafnia alvei by morphological, physiological and biochemical characterization and 16S rRNA sequence analysis, and its biological properties such as resistance to antibiotic, salt, acid and alkali, swimming motility and biofilm formation capacity were evaluated. Results showed that HY-1 was resistant to a wide range of antibiotics, which was moderately susceptible to tetracycline, erythromycin, penicillin G, ceftazidime, and cefuroxime axetil, and was resistant to midecamycin, clindamycin, clarithromycin, oxacillin, cephalothin, and cefazolin. HY-1 could grow in media at pH 5.0–8.0 containing 0.2–0.5 g/mL of sodium chloride at 4–37 ℃, and showed swimming motility as evidenced by the halo on the surface of the swimming plate. In addition, HY-1 could form biofilms, and milk at 2 mg/mL had the potential to facilitate biofilm formation by HY-1 and consequently increase its transmission and contamination, which may cause food quality and safety problems. However, when the concentration of NaCl equaled or exceeded 0.4 g/mL, the biofilm formation ability of HY-1 was significantly inhibited, indicating that the transmission and contamination of HY-1 could be intercepted by appropriate concentrations of NaCl.

Milk is a specialized substance secreted by the mammalian mammary gland and is the material basis for the survival and development of mammals. Understanding the similarities and differences in the milk composition of humans and domesticated mammals and gaining deeper insights into the characteristics of different mammalian milks will help in the targeted development and promotion of different mammalian dairy products. In this review, we summarize the main nutritional components in different mammalian milks and compare the composition and content of protein, fat and lactose, finding that there are large differences in these milk components. Besides, we review the functions and applications of different mammalian dairy products according to the conclusions drawn from the comparison.