A Survey of Bacteriological Quality and the Occurrence of Salmonella in Raw Bovine Colostrum

Abstract

In recent years, bovine colostrum has gained popularity as a human food because it is an excellent source of bioactive proteins, which have been claimed to inhibit viral and bacterial pathogens, improve gastrointestinal health, and enhance body condition. A study was conducted to determine bacteriological quality and occurrence of Salmonella in colostrum collected from dairy herds (n = 55) in Pennsylvania. Colostrum samples were analyzed for standard plate count, preliminary incubation count, laboratory pasteurization count, Staphylococcus aureus, Streptococcus agalactiae, coagulase negative staphylococci, streptococci, coliforms, and non-coliforms. A standardized polymerase chain reaction assay was used for detection of Salmonella in colostrum. Salmonella were detected in 8 of 55 (15%) of colostrum samples. Streptococcus agalactiae (1000 colony-forming units [CFU]/mL) was detected in one colostrum sample. The mean standard plate count (977,539 CFU/mL), preliminary incubation count (12,094,755 CFU/mL), laboratory pasteurization count (615 CFU/mL), Staphylococcus aureus (306 CFU/mL), coagulase negative staphylococci (164,963 CFU/mL), streptococci (256,722 CFU/mL), coliforms (323,372 CFU/mL), and non-coliforms (111,544 CFU/mL) counts in colostrum were considerably higher than raw bulk tank milk counts reported previously from Pennsylvania. Analysis revealed that farm size did not influence the bacteriological quality of colostrum. Collection, handling, and storage of colostrum need to be addressed to improve bacteriological quality of colostrum intended not only for feeding calves but also for human consumption.