Preliminary quality assessment of bovine colostrum

Data on bovine colostrum quality are scarce or absent, although Commission Regulations No 1662/2006 and No 1663/2006 include colostrum in the context of chapters on milk. Thus the aim of the present work is to study some physical, chemical, hygiene and safety quality parameters of bovine colostrum samples collected from Sicily and Calabria dairy herds. Thirty individual samples were sampled after 2-3 days from partum. The laboratory tests included: pH, fat (FT), total nitrogen (TN), lactose (LTS) and dry matter (NM) percentage (Lactostar) and somatic cell count (CCS) (DeLaval cell counter DCC). Bacterial counts included: standard plate count (SPC), total psychrophilic aerobic count (PAC), total, fecal coliforms by MPN (Most Probable Number), sulphite-reducing bacteria (SR). Salmonella spp. was determined. Bacteriological examinations were performed according to the American Public Health Association (APHA) methods, with some adjustements related to the requirements of the study. Statistical analysis of data was performed by Spearman’s rank correlation coefficient. The results showed a low variability of pH values and FT, TN and DM percentage between samples; whereas LTS trend was less noticeable. A significant negative correlation (P<0.01) was observed between pH, TN and LTS amount. The correlation between LTS and TN contents was highly significant (P<0.001). Highly significant and negative was the correlation (P<0.001) between DM, NT and LTS content. SPC mean values were 7.54 x106 CFU/mL; PAC mean values were also high (3.3x106 CFU/mL). Acceptable values of coagulase positive staphylococci were showed; 3 Staphylococcus aureus and 1 Staphylococcus epidermidis strains was isolated. Coagulase negative staphylococci counts were low. A high variability in the number of TC, as for FC was observed; bacterial loads were frequently fairly high. Salmonella spp. and SR bacteria were absent. It was assumed that bacteria from samples had a prevailing environmental origin; colostrum was also subject to a fecal contamination, frequently found in samples. The majority of samples had a high SCC, probably for a stress situation during cows birth. Statistical analysis showed a highly significant correlation (P<0.001) between SPC and PAC. Faulty samples conditions must lead to a great accuracy during controls of raw colostrum by the competent authorities. The examined farms need some interventions, aimed at optimizing all aspects of management, in view of the improvement of product that is used both for calves feeding and human destination.