MICROBIOLOGICAL SURVEY OF A SOUTH-AFRICAN POULTRY-PROCESSING PLANT

Bacterial populations associated with poultry processing were determin ed on neck skin samples, equipment surfaces and environmental samples by replicate surveys. Aerobic plate counts, Enterobacteriaceae counts and Pseudomonas counts were performed by standard procedures and the p revalence of Listeria, presumptive Salmonella and Staphylococcus aureu s determined. Statistically significant (P < 0.05) increases in counts of all types of bacteria were obtained on product samples as a result of processing. Although bacterial counts on neck skin samples decreas ed by 0.3 to 0.4 log CFU g(-1) after spray washing of carcasses, subse quent spinchilling and packaging of whole carcasses resulted in 0.7 to 1.2 log CFU g(-1) increases. Bacterial numbers on equipment surfaces, however, decreased significantly from the ''dirty'' to the ''clean'' areas of the abattoir. Transport cages, ''rubber fingers'', defeatheri ng curtains, shackles and conveyor belts repeatedly showed aerobic pla te counts in excess of 5.0 log CFU 25 cm(-2). Aerobic plate counts of scald tank and spinchiller water were 2 log CFU ml(-1) higher than tho se of potable water samples. Bacterial numbers of the air in the ''dir ty'' area were higher than those of the ''clean'' area. Listeria, pres umptive Salmonella and Staphylococcus aureus were isolated from 27.6, 51.7 and 24.1 % of all product samples, respectively, and Listeria and Staphylococcus aureus were also isolated from selected equipment surf aces.