Microbiological quality of raw donkey milk from Campania Region

Abstract

Microbiological quality of raw milk from eight healthy donkeys reared in Campania Region was investigated. A total of 152 samples were analyzed in order to evaluate the milk safety status trough monitoring mesophilic total bacterial count (TBC) at 32°C and 20°C, psychrophilic TBC at 5°C, Enterobacteriaceae, Salmonella spp., Listeria monocytogenes, Staphylococcus aureus and somatic cell count (SCC). The ranges for mesophilic bacteria at 32°C, 20°C and psy- chrophilic bacteria at 5°C were, respectively, 2.80–4.00 Log CFU/mL, 2.84–3.92 Log CFU/mL and 1.27–2.12 Log CFU/ml. Enterobacteriaceae showed a load ranging between 0.68–1.93 Log CFU/mL. No pathogenic bacteria were isolated. Estimated SCC values were always under 50.000 cells/mL. Additionally quantitative changes of bacterial population in raw bulk milk during eight storing days at 8°C and 3°C, were evaluated. Firstly, fresh bulk milk was contaminated by bacteria with a mean TBC at 32°C and 20°C of 2.71 Log CFU/mL and 2.64 Log CFU/mL, respectively, whereas TBC at 5°C and Enterobacteriaceae were not detected. After eight days of storage at 8°C, TBC at 32°C, 20°C and Enterobacteriaceae increased by three Log and TBC at 5°C by five Log. On the other side, after eight days of storage at 3°C no gradual Log increase was detected. Our results showed that donkey milk could be a good healthy ingredient for feeding where good hygienic procedures are applied and storage is kept at temperature lower than 3°C.