Abstract
This study investigated whether the storage temperature and mixing by repeated inversion of the container before sample inoculation for culturing affected the colony counts of specific bacteria, using milk containing E. coli, and 12 quarter milk samples from cows with clinical mastitis. The inoculation tools were also examined by comparing loops and swabs with the traditional method of using a micropipette and spreader. The colony counts given by E. Coli milk samples kept at 4℃ for 3 hours decreased significantly(p<0.05)and the colony counts of both the E. Coli milk and mastitis milk samples kept at 37℃ for 3 hours increased significantly(p<0.05)compared with the colony counts of those inoculated without storing. The inversion-mixed mastitis samples gave significantly(p<0.01)higher colony counts than the samples left standing for 3 hours. When inoculated using loops, the E. Coli milk samples gave significantly(p<0.01)higher and the mastitis milk samples gave significantly(p<0.05)lower colony counts than those inoculated by the traditional method. The colony counts of both E. Coli milk and mastitis milk samples inoculated using swabs were significantly(p<0.01)lower than those inoculated by the conventional method. Therefore, it is recommended that milk samples be kept at a low temperature and inversion-mixed before inoculation. The inadequacy of loops and swabs as inoculation tools was demonstrated.
