A Study of the Bacterial Population Fluctuations During Poultry Processing

The mz"crobz"al assessment of skz"n-washed water samples taken from 39 poultry carcasses and the wash water from a poultry processz"ng unz"t revealed cumulatz"ve z"ncreases z"n the number of mz"croflora at each stage ofprocessz"ng. A comparzson of the bacterz"al population densz"tz"es on the skz'n at the' start and at the end ofprocessz"ng showed that the levels of E. coli and coliforms z"ncreased by 231.1 % and 263.1 % respectz"vely whereas the Salmonella concentratz"ons decreased by about 9%. A posz"tz"ve correlatz"on was obtaz"ned between the occurrence of bacterz"a and parameters such as wash water pH and temperature, and suspended solz'ds concentratz"on. An examz"natz"on of the storage tank effluent whz"ch was used to store the poultry carcasses prz"or to packagz"ng showed that E. coli and Salmonella were able to thrz"ve z"n the lz'quz"d. Durz"ng the 4 h z"ncubatz"on perz"od, the levels of both organzsms declz"ned rapz"dly during the z"nz"tz"al half hour, but quz"ckly became adapted and multz"pUed z"n the subsequent hours. The z"mplz"catz"ons of both, the fz"eld and laboratory studz"es are dzscussed wz"th a vz"ew ofreducz'ng the level of contamz"natz"on durz"ng processz"ng. INTRODUCTION With. the increase in the price of fish, beef and other meats, more consume~have turned to poultry' as an alternative source of protein. In contrast to the beef industry which is well regulated in terms of standards of slaughtering and processing, the poultry meat industry consists of numerous independent entities whic~ manage their own slaughtering, cleaning and packaging activities, and which supply dressed chicken carcasse~ locally. It is likely that the demand for poultry meat will increase in the future since it is relatively cheaper than beef and other meat and this would result in the establishment of many poultry processing units or· plants in the country. M.1. YAZIZ AND R. AWANG One consequence of such an occurrence would be a lowering of quality control standards due to the volume of chickens being processed. Therefore some contamination will occur, the degree depending on the stage of processing, the sanitary conditions of the processing units, the temperature of the scald water, the equipment that they use and the personal hygiene practices of the personnel. In a fully automated processing plant or unit where manual contact is minimised, contamination will be low (Walker & Ayres, 1956) but the same may not be true in an ordinary or isolated processing unit. This study was designed to examine the extent and source of contamination in a poultry processing unit situated in Selangor. MATERIALS AND METHODS Poultry Processing Unit Approximately 150 to 250 birds are slaughtered on each occasion three times a week for sale to clients. However, during the festive seasons, the number increases to 350 to 400 birds whence some spoilage occurs during storage of the processed chickens prior to their sale. Slaughtering usually starts at about 0730 hand by 1000h all of the chickens would have been processed and wrapped in plastic bags ready for sale. About 4 to 6 workers are employed in the unit depending on the work load. Samples and Sampling Locations Figure 1 shows a schematic layout of the processing unit. The sampling sites are marked X. Due to time and limited manpower, samples were taken once weekly between 0900 hand 1100 h for 13 weeks. At each sampling site, liquid effluent or skin washings were collected in triplicates. The liquid effluent samples included water taken from the nearby stream, diluted blood and water from the drains surrounding the processing area, scald water from the scalder, water Legend: L sliquid samples skin/tissue wash samples Picker x(S2)