A RESEARCH NOTE MICROBIOLOGICAL QUALITY OF BROILER CHICKEN CARCASSES PROCESSED HYGIENICALLY IN A SMALL SCALE POULTRY PROCESSING UNIT

A RESEARCH NOTE MICROBIOLOGICAL QUALITY OF BROILER CHICKEN CARCASSES PROCESSED HYGIENICALLY IN A SMALL SCALE POULTRY PROCESSING UNIT K.P. YASHODA, N.M. SACHINDRA, P.Z. SAKHARE and D. NARASIMHA RAO' Department of Meat, Fish and Poultry Technology Central Food Technological Research Institute Mysore. India 57 1 3 Accepted for Publication March 27, 2 ABSTRACT Though large-scale entevrises in highly-developed countries of en produce millions of items in a single day, world-wide the volume of food produced in small-scale enterprises or at home in countries still developing is of great economic importance and hygienic concern. Trials were conducted to determine the degree to which the sanitary state of broilers processed on a small scale could be improved through the application of simple hygienic practices. Dressed broiler chickens were examined for microbiological quality. Live birds carried high microbial load (log @/em2): TPC 5.34; S. aureus 3.8 and fecal streptococci 3.2. The evisceration process resulted in a significant (P s.5) increase in microbial fecal contamination. Statistically significant lower microbial counts were observed in hygienically processed carcasses as compared with market carcasses. E. coli and fecal streptococci were completely absent in hygienically processed carcasses. Modest changes in processing methods resulted in broilers more hygienic with a gain in sherf-life compared with those regularly available on the market. INTRODUCTION The poultry industry is rapidly growing in India. Poultry meat is becoming more popular in the consumer market because of advantages such as easy digestibility and acceptance by the majority of people. At present only 4% of poultry processing in India is carried out in modern processing plants (Anon. 1994). The remaining 96% of the units are in the unorganized sector. Smallscale processing involving 3-5 birds/day is common in these units. In other ' Corresponding author Journal of Food Quality 24 (21) 249-259. AN Rights Reserved. "Copyright 21 by Food & Nutrition Press, Inc., Trumbull, Connecticut. 249

25 K.P. YASHODA, N.M. SACHINDRA, P.Z. SAKHARE and D. NARASIMHA RAO words, large quantity of poultry meat is processed by artisanal methods in small-scale processing units. The prevailing conditions in the majority of these units are not satisfactory from a hygienic point of view due to lack of proper infrastructure, lack of sufficient clean water, insanitary situations during scalding, evisceration and washing, and lack of refrigeration once the birds are dressed. Prolonged use of scald water and improper method of evisceration can lead to an increase in microbial load of the carcasses. Simple changes during processing can have profound effects on the sanitary state of market poultry; in turn poultry meat of a more sanitary quality leads to less risk of illness for consumers. Trials are needed to demonstrate even modest processing changes can enhance the welfare of consumers. Consumers are becoming aware of the danger of illness that arises from insanitary conditions, and they are even prepared to pay more for carcasses less contaminated. The majority of the population depends on the poultry meat available in the market. Small-scale poultry processing units (3-5 birds/day capacity) are most suitable for hygienic processing of poultry in developing countries, since investments are less. It is easy to control sources of microbial contamination and achieve better quality of carcasses in small sized poultry processing units. The significance of the sources of microbiological contamination has been studied during poultry processing over the years. Scalding, plucking and evisceration were found to be the major critical points of contamination (Brown 1957; Ayers 196; Cunningham and Cox 1987; Thomas ef al. 1987). Hygiene plays an important role during processing in the prevention of initial contamination of meat and poultry (Smulders 1987 and Narasimha Rao ef al. 1998). Mossel ef al. (1999) stated that there is a need for an approach to assure microbiological safety assurance in small businesses in the food sector worldwide. The poultry meat working group of Advisory Committee on the Microbiological Safety of Foods, Govt. of UK, in its report (Anon. 1996) pointed out the importance of adopting HACCP principles in production, processing and handling of poultry meat to achieve a pathogen free product. It was reemphasized that there is a need for improvements in hygiene during processing of poultry from the point of the application of HACCP principles (Bolder 1998; Davies and Board 1998). The objective of this study was to identify the critical points of microbial contamination during processing of broiler chicken in a small scale processing unit and to investigate the effect of hygienic procedures during processing on microbiological quality and shelf-life of broiler chicken.

SMALL SCALE PROCESSING OF CHICKENS 25 1 Small Scale Processing Unit MATERIALS AND METHODS The poultry processing unit at CFTRI has a slaughter capacity of 5 broilers per hour. The unit has a lairage, slaughter unit, and facility for scalding, evisceration and washing. The equipment include slaughter cones, scald tank, defeathering (picking) machine, overhead rails, gambrels (shackles), stainless steel tables, and stainless steel tanks. Processing of Broiler Chicken All the processing operations were carried out manually except defeathering. Live birds were put in slaughter cones and slaughtered by cutting the neck, and the blood allowed to drain out into a trough. The slaughtered birds were scalded at 58-6C for 1 min in a scalding tank. The temperature of the scald water was maintained by a thermostat. The scalded birds were defeathered using a picker with rotating rubber fingers. The defeathered birds were hung on overhead rails, eviscerated manually and washed with clean water. Hygienic Procedures Followed The walls, floor, equipment and knives were washed thoroughly before and after operation with liquid soap, clean water, then with hot (85C) water and with a final wash of 7 ppm chlorine. Hands of the personnel were washed with soap and chlorinated water before, after, and in-between operations. All the operations were done off the floor. The birds were eviscerated without damaging the visceral content. By-products and wastes were kept separate and removed immediately. The carcasses were washed thoroughly after each operation using chlorinated water sprays. Microbiological Examination of Carcasses To determine the points of microbial contamination during processing, samples were taken for microbiological analysis at different stages of processing: live bird, after scalding, after defeathering, after evisceration and after washing. The scald water was analyzed for microbiological quality after scalding 1, 2, 5, 1, 15 and 2 birds. This experiment was repeated six times in order to detect the point at which scald water has to be replaced. For comparison carcasses collected from the market (where scald water is not replaced regularly, scald water temperature is not maintained, defeathering is done manually, evisceration is done without following any hygienic measures and all operations are done on the floor) were also analyzed. The carcasses, both hygienically processed and

252 K.P. YASHODA, N.M. SACHINDRA, P.Z. SAKHARE and D. NARASIMHA RAO from the market were packed in polyethylene pouches, stored at 4+1C, and analyzed periodically for microbiological quality. Microbiological Analysis Sampling of carcass surfaces was done with a swab at two sites (leg and breast) with a total surface area of 32 cm2. During storage, 25 g of meat samples (from leg and breast) were taken for analysis. Scald water for analysis was collected in sterile bottles. The samples were subjected to microbiological analysis according to standard procedures (APHA 1992), for total mesophilic plate count (TPC) (37C, 48 h) and psychrotrophs (15C. 7 days) on plate count agar, yeast and mold counts on potato dextrose agar (37C, 48 h), Sraphylococcus aureus on Baird Parkar agar (37C, 48 h). fecal streptococci on KF Streptococcal agar (37C, 48 h), E. coli on EMB agar (37C, 48 h) and coliforms by MPN technique in brilliant green bile broth (37C, 48 h) (Hi-Media, Mumbai, India). Statistical Analysis Differences in microbial counts were examined for significance by analysis of variance, and when significant difference was observed, means separation was accomplished by Duncan s multiple range test using the software SPSS for windows (SPSS Inc. 1992). Points of Microbial Contamination RESULTS AND DISCUSSION The microbial load on broiler chicken carcasses at different stages of processing is presented in Fig. 1. Live birds carried a particularly high microbial load, TPC (5.34 log cfu/cm2), S. aureus (3.8 log cfu/cm2) and fecal streptococci (3.2 log cfu/cm2). Feathers and skin of broilers entering a processing plant may have high numbers of human pathogens (Kotula and Pandya 1995). Physical separation of live bird areas from the processing area has been suggested as one of the means of minimizing the transfer of microorganisms from live birds to processed carcasses (Patterson 1971; Mead 1976). Scalding of birds reduced the microbial load significantly (p 5.5) with a reduction of 1.9 log in TPC,.58 log in yeast and mold count, 1.69 log in fecal streptococci and 1.58 log in S. aureus count (Fig. 1). Mead (1976) and Nottermans er al. (1977) reported a reduction in the counts of S. aureus, coliforms and mesophiles due to scalding. Scalding partially eliminates the initial flora on poultry skin, but subsequent recontamination takes place mostly by Gram negative organisms (Barnes 1976; Daud et al. 1979).

7 SMALL SCALE PROCESSING OF CHICKENS 253 b 5 T 6 5. N 5 2 9 -I 2 1 a d 4 N 6 3 z I E 2 ;.- 1 Total Plate Yeast & S. aureus Fecal Coliforrns Count Molds Streptococci FIG. 1. MICROBIAL LOAD ON BROILER CARCASSES AT DIFFERENT STAGES OF HYGIENIC PROCESSING (n = 12) Bars with different superscripts differ significantly p <.5) e3 Live birds El After Scalding E4 After Defeathering After Evisceration IJAfter Washing The build up of microbial load in scald water is a problem in improving the microbiological quality of poultry. Scalding results in the release of a large load of organic matter, microbes, and fecal material to the scald water (Kotula and Pandya 1995). The accumulated fecal material in scald water dissociates to form ammonium urate and uric acid, which act as a natural buffering system to maintain the ph of water around 6., the ph at which salmonellae are more heat resistant (Humphrey and Laming 1987). Further, the scald water with its contaminants may enter the trachea and can invade the air sac and may contaminate the internal organs and edible tissues (Lillard 1973). This calls for a strict monitoring of scald water quality. The need for replacing scald water periodically can be stressed from the results of this study, which indicated that the counts between scalding the first and tenth bird increased gradually, but significantly (p 5.5) by 1.2 log in TPC,.79 log in yeast and mold,.35 log in S. aureur,.28 log in fecal streptococci and 13.1 MPN/mL in coliforms (Table 1). Similar observations have been made by Mulder and Veerkamp (1974), who reported that after an initial increase in bacterial counts of the scald water, it remains relatively constant throughout the processing day. However, before the counts increase

254 K.P. YASHODA, N.M. SACHINDRA, P.Z. SAKHARE and D. NARASIMHA RAO significantly further, it is advisable to change the scald water frequently to minimize the contamination. Scalding is a batch operation in many of the small-scale processing units in India. This study identified the need for change of scald water frequently. The procedure is practical in small-scale poultry processing plants. TABLE 1. MICROBIAL LOAD OF SCALD WATER AS AFFECTED BY NUMBER OF BfRDS SCALDED (n = 6) After Scalding -_ - -- - -._ - - - - - -_- - 1 bird 2 birds 5 birds 1 birds 15 birds 2 birds -~. -- -- Total Plate Count 32" 332b 387" 422d 425d 4 3d (log cfulrnl) 24 NO3 i 11 LO6 +8 2 14 Yeast and Mold (log cfulml) 1 5a 9 +_o S aweus 1 3" (log cfulml) 5.14 Fecal Streptococci 1.5" (log cfu/rnl) 1 19 Coliforrns 8 7= (MP Nlml) - 52.4 1 72b i 29 1.57ab *o 34 1.56ab +O 26 1 7" k1.4 1 83bC 1 7 1 mbc 1 3 1 6gabc d 13 16 Ob i3 4 -. ~- 1 84bc to 9 1 7bC -1 24 1 7ebC 1 15 21 8' *2 4 1 9gC 1 8 1 95Cd LO 15 1 8C 1 14 23 gcd -1-23 2 55" 4 9 2 3 1 12 185"!O 1 25 5d 12 79 Values in rows with different superscripts differ significantly (p 5 5) During defeathering there can be considerable spread of microorganisms from carcass to carcass and from the defeathering equipment itself (Mulder e? al. 1978; Bryan 198; Mead 1992). It is interesting to note that in the present study the defeathering operation did not contribute significantly towards microbial build up on carcasses. However, frequent washing of defeathering fingers is necessary as it was demonstrated that the microbiological load on plucker fingers builds up during progress of the operation (Whittemore and Lyon 1994; Bolder 1998). The process of defeathering also appears to equalize the microbial population among carcasses as the operation progresses (Shackelford e? al. 1993). This suggests that even though in the present study defeathering resulted in only a marginal increase in microbial counts, it would be advisable that even in small-scale processing units, where batch type defeathering machines are used, frequent washing of plucker fingers is necessary.

SMALL SCALE PROCESSING OF CHICKENS 255 The evisceration process resulted in a significant (p S.5) increase in microbial counts particularly that of fecal streptococci (.93 log) and coliforms (34.43 MPN counts). Nottermans et al. (198) reported that aerobic mesophiles usually do not increase significantly during evisceration, but the number of enterobacteriaceae often increases. This indicates that care during evisceration to avoid fecal contamination of carcasses is necessary. Effect of Hygienic Processing General hygiene in the poultry processing plants, which in turn influences the microbiological quality of poultry carcasses, depends on the design of the plant and building, raw material quality, sanitization of equipment, personnel hygiene and cleaning efficiency (Patterson 197 1). Following of hygienic measures is particularly important in the case of small-scale processing units, as most of the processing operations are carried out manually. In the present study, the hygienic measures followed were found to improve the microbiological quality of broiler carcass as compared with market meat where generally no hygienic measures are followed. The microbial counts of hygienically processed and market carcass is shown in Fig. 2. E. coli and fecal streptococci were completely absent in hygienically processed carcasses. The high counts in the market meat indicate the need to practice hygienic procedures. '1 6 15 125 N E 1s a E 25 Total Plate Yeast & Mold Psychrotrophs Saureus Coliforms Count FIG. 2. MICROBIAL PROFILE OF FRESH BROILER CHICKEN CARCASS - HYGIENICALLY PROCESSED (HPC) V/s MARKET MEAT (MTC) (n= 1)

.f.. 256 K.P. YASHODA, N.M. SACHINDRA, P.Z. SAKHARE and D. NARASIMHA RAO The importance of hygienic processing is reflected in extension of shelf-life of hygienically processed broiler chicken at refrigerated temperature (Fig. 3). The TPC in carcasses from market reached a level of 6.32 log cfu/g and psychrotrophs a count of 5.14 log cfu/g by 48 h. In comparison the counts in hygienically processed carcasses increased gradually reaching a high level (TPC: 5.9 log cfu/g and psychrotrophs: 5.8 log cfu/g) by the fifth day at 4+ 1C. This improvement in shelf-life of hygienically processed meat is mainly due to the lower initial bacterial counts. Initial bacterial counts affect the shelf-life of poultry meat (Brown 1957; Ayres 196; Svendson and Caspersen 1981; Cunningham and Cox 1987; Cox e? al. 1998). Total Plate Count Psychrotrophs 7 6 6. E, $ 5 J 4 4 3 Spoiled... ~ f 3 I I 1 I 1 2 3 4 5 1 I, 7 1 2 3 4 5 Days at 451 C FIG. 3. CHANGES IN THE MICROBIAL PROFILE DURING STORAGE OF BROILER CHICKEN CARCASSES AT 4* 1C - HYGIENICALLY PROCESSED (HPC) VERSUS MARKET MEAT (MTC). (n= 1) --+--HPC +MTC It can be concluded from the study that live birds, scald water and evisceration processes are major sources of microbial contamination in small-scale poultry processing units. In order to minimize the contamination

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