Department of Animal Products Technology & Marketing,. West Bengal University of Animal & Fishery Sciences,. 37, K.B. Sarani, Kolkata-37, West Bengal.
J. Vet. Publ. Hlth., 2003, 1 (2) : 147-152
Effect of Processing Methods on Microbiological Quality of Chicken Arun K. Das· and S. Biswas
Department of Animal Products Technology & Marketing,
West Bengal University of Animal & Fishery Sciences,
37, K.B. Sarani, Kolkata-37, West Bengal
Received: 27.12.2003
Abstract A study was conducted to evaluate the effect of two different processing methods on sanitary quality of chicken produced in processing plant and proc essed by conventional method and sold at retail outlets. Meat samples collected were subjected to total plate count (TPC), psychrotropic count (PC), coliform count (CC), staphylococal count (SC), faecal streptococci count (FS) and yeast and mould count (YMC). TPC (log cfu/cm') of chicken meats collected from scientific method and conventional method, were 4.12 and 5.75, respectively. The samples collected from scientific slaughtering method showed mean PC, CC, SC, FS and YMC of 1.67, 2.18, 1.89, 1.24 and 2.08 log cfu/cm', respec tively. The respective microbial counts for conventional processing method were 3.25,3.73,2.46,3.57 and 2.97 log cfu/crn', respectively. The study also showed that breast muscle had higher microbial load than the thigh muscle in both the processing methods. The results in this study indicated that chicken parts proc essed under conventional roadside methods could represent notable hazards to human health.
Keywords: chicken, microbiological quality, processing methods.
Introduction Indian poultry industry, especially broiler production, has made a phenomenal progress in the last few decades. However, parallel with the production, commercial processing of poultry and further process ing of poultry products have not taken place with the same speed and pace as desired. *Present address
Division of Livestock Products Technology, IVRI,
Izatnagar, BareiHy- 243 122 (D.P.)
Only about 10% of the total bird popula tion are processed through modern process ing plant maintaining the hygienic standards while rest are slaughtered without stunning and dressed in roadside shops or booths in the local market in presence of consumers. When the birds are processed at retailer's shop, little attention is paid to their hygi enic condition. As a result, the product is likely to harbour various types of undesir able microorganisms in the finished prod ucts. This not only acts as potential danger
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for human health but at the same time bring about a rapid deterioration in quality of the product resulting in heavy economic losses during the process of storage and market ing (Panda, 1971). Though consumption of poultry meat has increased steadily, the presence of patho genic and spoilage microorganisms in poul try meat remains a major concern for sup pliers, consumers and public health officials worldwide. During slaughtering, dressing and further processing, meat surface invari ably comes in contact with contaminated tools and equipments and get easily con taminated (Narsimha Rao and Ramesh, 1988). Meshophiles, psychrotrohes, coliform, staphylococci, salmonellae, Pseudomonas, enterococci, yeast and mould have been used in poultry meat to assess microbiological safety, sanitary condition during slaughtering and processing and keeping quality of meat foods (Tompkin, 1983; Russell, 1997). Keeping this in view, the present study was under taken to evalu ate the microbiological quality of chicken processed under scientific and conventional methods of processing.
Materials and Methods In the present study, chicken carcasses processed in conventional method, were collected from local market maintaining the uniformity in terms of age, flock, body weight and body conformation. In this method, retailers collected the birds from the traders one day earlier without ante mortem examination. The birds were al lowed to eat maximum feed to get higher
body weight. The birds were instantaneously slaughterea and were not allowed for com plete bleeding and skin was removed along with viscera without defeathering and singe ing. A bucketful of water was generally used again and again for washing the carcass, appliances and hands of sellers. The whole procedure is performed within a couple of minutes over a wooden block generally in open air or under a shed within a congested market in front of the consumers. Among the viscera, gizzard was freed from undigested feed and washed in the same bucketful of water by dipping. Such car casses were transported in sterile low den sity polyethylene bags to the laboratory under ice for further investigation.
In scientific method, the birds were fasted for 24 h with ad libitum potable wa ter. Birds were slaughtered by Halal method and sufficient time was given for bleeding. The birds were scalded, defeathered, singed and eviscerated with sufficient care for maintaining hygienic standard. Such car casses were then used as materials for the experiments. Microbial counts on the surface of carcasses were determined by wet swab technique as described by Burne and Cunningham (1971). The swab was placed in a test tube containing 10 ml of peptone water. Appropriate dilutions were inoculated into media using standard spread plate tech nique (APHA, 1984). Following incubation, plates showing 30-300 colonies were counted and expressed as log cfu/cm", Data obtained were analyzed statistically.
Effect of processing method on microbiological quality
Results and Discussion Mean values of the standard plate count (log cfu/crrr') of meat samples proc essed under scientific method in processing plant were recorded to be 4.15 and 4.09 in breast and thigh muscles, respectively (Ta ble I). These counts were almost similar to those recorded earlier in meat samples (Sofos, 1994). Chicken processed under conventional method showed significantly (p< 0.05) higher TPC counts (5.86 and 5.65 in breast and thigh muscles, respectively) than the scientific method. Such differences of TPC value in terms of method was in conformity with the finding of Narsirnha Rao (1998), where he noted similar trend in meat samples collected from modern processing plant and retail shops. This high count could be due to poor hygienic stand ard practiced at retail shops under conven tional method. Moreover, sources of mi crobes in this method are numerous as mi crobes could get access into the meat through water and appliances used during processing. All the meat samples (processed in retail shops) examined were found to be positive for the presence of coliforms. The mean coliform counts (2.18) of meat sam ples from processing plant were 2.21 and 2.13 in breast and thigh muscles, respec . tively (Table 1). Izat et al. (1989) also re corded similar trend. Significantly higher (p
