2003 Poultry Science Association, Inc.
Effect of Commercial Bird Washers on Broiler Carcass Microbiological Characteristics J. K. Northcutt,1 M. E. Berrang, D. P. Smith, and D. R. Jones USDA Agricultural Research Service, Russell Research Center, P.O. Box 5677, Athens, Georgia 30604-5677
Primary Audience: Poultry Processors, USDA Personnel, Researchers SUMMARY A study was conducted to determine the effects of commercial bird washers on broiler carcass microbiological characteristics. Broiler carcasses were removed from the processing line in 3 different commercial facilities immediately before and after the inside-outside bird washer (IOBW). Whole carcass rinses were analyzed for coliforms, Escherichia coli, and total aerobic bacteria. Coliform, E. coli, and total aerobic bacteria counts on carcasses varied among the processing plants evaluated (P < 0.05); however, no difference was found for carcass coliform or E. coli counts due to washing in the IOBW. Total aerobic bacteria decreased significantly on carcasses from plant 3 (4.4 log10 versus 3.8 log10) after washing in the IOBW, but this trend did not occur at all of the plants evaluated. These data show that use of the IOBW may not significantly reduce carcass coliform or E. coli counts. Key words: broiler, carcass contamination, bird washer 2003 J. Appl. Poult. Res. 12:435–438
DESCRIPTION OF PROBLEM On July 25, 1996, the United States Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) published a ruling on pathogen reduction and Hazard Analysis and Critical Control Point Systems (HACCP) for poultry and meat establishments [1]. This ruling was designed to improve the safety of meat and poultry by requiring establishments to meet guidelines for sanitation and pathogen performance standards and by requiring the development and implementation of a scientific-based system (HACCP) for modernizing carcass inspection. According to the Pathogen Reduction (PR)/HACCP ruling, establishments that slaugh1
ter animals must allow USDA-FSIS to test carcasses for Salmonella, whereas the processing establishments must test carcasses for generic Escherichia coli. The PR/HACCP ruling further defines the performance standards that establishments must meet for both microorganisms. Recent reports regarding the PR/HACCP ruling have indicated that the changes it imparted have resulted in improved microbiological safety of meat and poultry, with pathogen performance levels well below the USDA-established standards [2]. To meet these pathogen reduction performance standards, processing establishments have implemented a series of operational changes, most of which have involved the use of additional water [3].
To whom correspondence should be addressed:
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436 According to the USDA-FSIS, establishments are required to test carcasses for generic E. coli to verify that the establishment is meeting the zero-tolerance policy as stated in the PR/ HACCP ruling for removal of visible carcass fecal contamination [1, 4]. All visible fecal contamination must be removed from carcasses prior to the chilling operation by “trimming or washing, either on or off the processing line” [4]. The primary methods for removing carcass fecal contamination are cabinet washers, including inside-outside bird washers (IOBW), carcass sprays, and brush washers [3]. In a survey of poultry processing establishments, Jackson and Curtis [3] reported that some poultry processing establishments were using a series of IOBW after evisceration to comply with the PR/ HACCP ruling. Although the primary function of these washers is to remove visible fecal material from carcasses, little attention has been given to the relationship between carcass washers, other operational changes, and pathogen reduction performance standards of the PR/ HACCP ruling. Prior to the implementation of the PR/ HACCP ruling, several studies were conducted to examine the effects of washing and chilling with and without chlorine on carcass microbiological characteristics [5, 6, 7, 8]. Baker et al. [5], Izat et al. [6], and Lilliard [7] demonstrated that the number of pathogenic bacteria on carcasses decreased as they progressed through the processing establishment. May [8] evaluated carcass contamination at various stages of processing and reported low bacterial counts until evisceration. Moreover, eviscerated carcass counts remained high until after the final wash [8]. Merka [9] reported that 75% of the total water used in a commercial broiler processing establishment occurs during evisceration; however, this report was published prior to the PR/ HACCP ruling. Water usage during evisceration may now account for more than 75% of an average plant’s total water consumption. For this reason, the present study was designed to evaluate the effectiveness of commercial IOBW on carcass microbiological characteristics. IOBW were chosen because most commercial models use between 150 and 360 L (40 to 95 gal) of water per minute, and one IOBW in a processing
establishment may account for as much a 2% of the plant’s total water consumption per day.
MATERIALS AND METHODS Sampling On each of 3 different sampling days (replicate), 10 carcasses were removed from a commercial processing line before (pre-) and after (post-) the IOBW. The 10 pre-IOBW carcasses and 10 post-IOBW carcasses were removed from the processing line simultaneously by 2 teams of researchers (2 people per team) to minimize flock-to-flock variation within replication. Carcasses were removed from the line with clean gloves and placed into clean plastic bags, and the bags were sealed using zip ties. Bags containing carcasses were placed into coolers with ice and transported to the laboratory for microbiological analyses within 2 h. Carcasses were collected from 3 different processing plants, on 3 different sampling days for each plant (30 pre-IOBW and 30 post-IOBW per plant). Immediately following carcass sampling, approximately 1 L (0.26 gal) of water was collected from the IOBW before and after contact with carcasses. Collection was accomplished by holding a previously autoclaved bottle in front of several nozzles or in front of IOBW discharge pipe. Water samples were placed on ice and transported to the laboratory for analyses. At the laboratory, water samples from the IOBW nozzles (pre) and discharge pipe (post) were analyzed for chlorine using the CHEMetrics 2 SAM test kit [10] Microbiological Analyses Upon arrival at the laboratory, each carcass was rinsed with 100 mL of sterile PBS and shaken vigorously in a 1-ft arc for 60 s. After shaking, carcasses were aseptically removed from the bags and discarded. Serial dilutions of the rinse were made in PBS. Total aerobic bacterial populations were enumerated on plate count agar [11]. A 0.1-mL sample from a serial dilution of the rinse diluent was plated in duplicate on the surface of the agar, spread, and incubated at 37°C for 18 to 24 h prior to counting the resulting colony-forming units. Coliform and E. coli counts were made by plating 1 mL from a serial dilution of the rinse diluent onto dupli-
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TABLE 1. Effect of processing plant and sampling site on mean log10 counts (n = 30) for coliforms, Escherichia coli, and total aerobic bacteria Plant
SiteA
1
Pre Post Pre Post Pre Post Plant Site
2 3 Probability
Coliforms 2.6 2.4 3.7 3.1 3.4 2.8
± 0.5bc ± 0.4c ± 0.7a ± 0.6ab ± 0.1ab ± 0.4abc 0.015 0.058
E. coli 2.2 2.1 3.3 2.7 3.1 2.4
± 0.4c ± 0.5c ± 0.7a ± 0.6abc ± 0.1ab ± 0.3bc 0.013 0.056
Total aerobes 3.8 ± 0.2c 3.4 ± 0.4c 5.0 ± 0.3a 4.7 ± 0.3ab 4.4 ± 0.1b 3.8 ± 0.2c 0.0001 0.003
Means (± standard deviation) in the same column without common superscripts differ significantly (P < 0.05). Site refers to before (pre) and after (post) carcass washing in the inside-outside bird washer.
a–c A
cate E. coli petrifilm plates [12]. Petrifilm plates were incubated at 37°C for 18 to 24 h, and colony types characteristic of coliforms and E. coli were enumerated. Statistical Analysis Data were analyzed by the ANOVA option of the general linear models procedure of the SAS/STAT program using plant, replicate, and site (before and after IOBW) as main effects [13]. All first order interactions were tested for statistical significance (P < 0.05) using the residual error mean squares. There were no significant replicate or interaction effects, and the data were pooled by replicate. Means were separated using the Duncan’s multiple-range test (P < 0.05) option of SAS software using the appropriate error as described.
RESULTS AND DISCUSSION The mean logarithmic microbial counts (log10) for coliforms, E. coli, and total aerobic bacteria on carcasses from different commercial poultry processing facilities pre-IOBW and postIOBW are shown in Table 1. Counts for coliforms, E. coli, and total aerobic bacteria varied among the 3 plants evaluated (P < 0.05), and counts were slightly higher (0.6 to 1.6 log10 greater) for carcasses from plants 2 and 3. Waldroup et al. [14] also concluded that incidence
rates and levels of pathogenic bacteria on carcasses are significantly different from plant to plant and that this difference results in a varied response to processing modification. Washing with the IOBW (site) had no effect on coliform (P = 0.058) or E. coli (P = 0.056) counts, but a significant effect was observed for total aerobic bacteria (P = 0.003) on carcasses. A 0.6 log10 reduction in total aerobic bacteria was found after washing with the IOBW in plant 3. Kemp et al. [15] reported that in many commercial facilities, a reduction of 1.5 log10 in E. coli or Salmonella was not sufficient to allow processors to comply with the USDA pathogen reduction standard [1]. These authors also reported a 0.6 log10 decrease in E. coli on poultry carcasses after washing in the IOBW [14]. Similar results have been reported for reductions in total microbial counts after washing and for reductions in Campylobacter [16]. All of the processing facilities evaluated in the present study indicated that they were used chlorine in their IOBW, but usage was inconsistent and varied widely from no additional chlorine added (0.5 to 1 ppm incoming from city water) to 33 ppm total chlorine before contact with carcasses. Because of the inconsistency with chlorination on the sampling days, no relationship between microbiological characteristics of carcasses and plant chlorine usage was observed during this study.
CONCLUSIONS AND APPLICATIONS 1. Coliform, E. coli, and total aerobic bacterial counts on broiler carcasses vary among commercial facilities.
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2. Under the conditions of this experiment, washing broiler carcasses in commercial IOBW did not appear to significantly reduce carcass coliform or E. coli counts, but carcass washing did reduce total aerobic bacteria counts. 3. Carcass bacterial reductions due to use of IOBW may increase with consistent chlorination of water.
REFERENCES AND NOTES 1. USDA, Food Safety and Inspection Service. 1996. Pathogen Reduction; Hazard Analysis and Critical Control Point (HACCP) System. Final Rule. Fed. Regist. 61:38806–38944.
9. Merka, W. C. 1989. Wastewater volumes discharged by a processing plant. Processing Tip, October. University of Georgia, Athens, GA.
2. USDA. 2002. Progress report on Salmonella testing of raw meat and poultry products. 1998–2001. www. fsis.usda.gov/OPHS/ haccp/salm4year.htm.
10. CHEMetrics Inc., Calverton, VA.
3. Jackson, W. C., and P. A. Curtis. 1998. Effect of HACCP regulation on water usage in poultry processing plants. Pages 434– 439 in Natl. Poult. Waste Manage. Symp. J. P. Blake and P. H. Patterson, ed. National Poultry Waste Management Symposium Committee, Auburn University, Auburn, AL.
12. 3M Health Care, St. Paul, MN.
4. USDA, Food Safety Inspection Service. 1998. FSIS clarifies and strengthens enforcement of zero tolerance standard for visible fecal contamination of poultry. www.fsis.usda.gov/OA/background/zerofcl.htm. 5. Baker, R. C., M. D. C. Paredes, and R. Q. Quereshi. 1987. Prevalence of Campylobacter jejuni in eggs and poultry meat in New York State. Poult. Sci. 66:1766–1770.
11. Becton Dickinson, Sparks, MD.
13. SAS. 1999. SAS/STAT User’s Guide. Release 8.0 ed. SAS Institute Inc., Cary, NC. 14. Waldroup, A. L., B. M. Rathgeber, and R. H. Forsythe. 1992. Effects of six modifications on the incidence and levels of spoilage and pathogenic organisms on commercial processed postchill broilers. J. Appl. Poult. Res. 1:226–234. 15. Kemp, G. K., M. L. Aldrich, M. L. Guerra, and K. R. Schneider. 2001. Continuous online processing of fecal- and ingestacontaminated poultry carcasses using acidified sodium chlorite antimicrobial intervention. J. Food Prot. 64:807–812.
6. Izat, A. L., F. A. Gardner, J. H. Denton, and F. A. Golan. 1988. Incidence and level of Campylobacter jejuni in broiler processing. Poult. Sci. 67:1568–1572.
16. Bashor, M. P., K. M. Keener, P. A. Curtis, B. W. Sheldon, and S. Kathariou. 2002. Effect of carcass washing systems on Campylobacter contamination in large broiler processing plants. Poult. Sci. 81(Suppl. 1):48–49. (Abstr.)
7. Lilliard, H. S. 1990. The impact of commercial processing procedures on the bacterial contamination and cross-contamination of broiler carcasses. J. Food Prot. 53:202–204.
Acknowledgments
8. May, K. N. 1961. Skin contamination of broilers during commercial evisceration. Poult. Sci. 40:531–536.
The authors express appreciation to Mark N. Freeman and Patricia Mason for their technical assistance during this project.
