Antibacterial activity of donkey milk against Salmonella
The aim of this study was to investigate the effect of initial contamination and lactation stage on the antibacterial properties of raw donkey milk against three Salmonella species in artificially contaminated milk samples during five days of storage at 4°C. Tested samples showed antibacterial activity against all three strains at three examined contamination levels (102, 103 and 104 CFU /ml). At the lowest level of contamination milk samples exhibited bactericidal activity. Milk from the early and middle lactation period showed a stronger antibacterial activity in comparison to the milk from the late lactation period. Lysozyme and lactoferrin content decreased during lactation. Antibacterial effect of donkey milk was confirmed by scanning electron microscopy.
Salmonella is one of the principal causes of foodborne illness worldwide and is equally present in developed and developing countries (2). Infections of Salmonella spp. occur in humans in two forms, as a typhoid fever, a systemic disease, and as salmonellosis, a self-limiting gastrointestinal illness (24). Milk and dairy products are a good medium for the growth of Salmonella spp., whose presence in milk is associated with the management of dairy animals, animal feed and storage conditions (15). Recent investigations showed that Salmonella was present in 3-6 percent of raw bovine milk samples (20), mostly at level of 200 CFU/ml, although there are reports about the raw milk samples with even 105 CFU /ml of Salmonella spp. Unlike bovine milk, there are much less literature data on Salmonella spp. in non-bovine milk, especially on donkey milk, which has been long time attributed significant medicinal and therapeutic properties (28, 29). Low casein content, high percentage of essential amino acids, protein and lipid profiles similar to those of human milk (28) are in favour of donkey milk as a potential new dietetic food and ...