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United States Department of Agriculture

Agricultural Research Service

Related Topics


Location: Poultry Processing and Swine Physiology Research

2009 Annual Report

1a.Objectives (from AD-416)
1) Develop and analyze poultry processing methods that utilize electrolyzed water and antimicrobial fatty acids as microbiocides to decrease microbial contamination during poultry processing. 2) Develop innovative processing operations and recommend modifications in existing processing operations to decrease water use in commercial poultry processing. 3) Evaluate the movement of microorganisms from broiler carcasses to processing water and equipment, specifically scalders, eviscerators and chillers.

1b.Approach (from AD-416)
Alternative antimicrobial treatments such as electrolyzed water, salts of fatty acids, peroxyacetic acid, blends of organic acids, chlorine dioxide, monochloramines, cetylpyridinium chloride and ozone will be evaluated for activity against poultry pathogens and spoilage bacteria. Optimum conditions for applying antimicrobials, including concentration and methods (spray or immersion), will be identified. Treatments with the greatest efficacy against poultry pathogens will be tested further during immersion chilling with reduced water volumes or air chilling. Carcass cross-contamination and procedures of preventing cross-contamination will be determined by focusing experiments on three of the processing areas where the transfer of bacteria is greatest (scalding, defeathering and equipment surfaces). Experiments will also evaluate product contact surfaces as a source of cross-contamination. Partitioning experiments will be performed to separate pathogens on the exterior of the bird from those interior. Cross-contamination will be minimized by using antimicrobial treatments tested in subsequent experiments. Research will be transferred to processing and regulatory personnel for implementation into Sanitation Standard Operating Procedures (SSOPs) and Hazard Analysis and Critical Control Point System (HACCP) plans.

3.Progress Report
Research was conducted to examine the ability of antimicrobial cleansers to reduce the contamination of the skin of processed broiler chickens by pathogenic and spoilage bacteria. Repeated washing of the skin in cleansers derived from lauric acid, a naturally occurring fatty acid found in coconut oil, indicated that washing skin in these substances reduced bacterial contamination of the skin. Also, studies on the antibacterial activity of monolaurin (a derivative of lauric acid) this substance could inhibit the growth of bacteria associated with poultry processing although monolaurin could not kill these bacteria. These compounds are being examined as alternatives to chlorine, which is widely used as a sanitizer in commercial poultry processing in the United States. However, broilers processed using chlorine cannot be imported into the European Union (EU); therefore, the development of acceptable alternatives to chlorine would open European markets to poultry processors in the U.S. Furthermore, water hardness may play a role in the ability of cleansers to remove bacteria from the surface of skin; thus, studies were also conducted to determine the effect of water hardness on the ability of water to wash microorganism from the skin of processed broilers.

Additional research was conducted to examine cross contamination of broiler carcasses during early processing operations. These studies showed that Salmonella and E. coli can survive in the elevated temperatures of the scalding operations and that these bacteria can be recovered from scalder water, scalder foam, and broiler carcasses taken from scalders in commercial processing facilities. Several Salmonella isolates were recovered from the samples taken from scald tank samples, and genetic-based tests were used to identify these isolates. These isolates were also characterized using a novel testing procedure developed at the Russell Research Center. Other cross contamination studies indicated that fecal material expelled by carcasses during processing may contaminate carcasses with bacteria pathogenic bacteria.

Further studies were conducted to compare sampling procedures and compliance standards used by regulatory agencies in the United States and in the EU. Research indicated that results obtained from sampling rinsates of whole carcasses or broiler neck skin was not significantly different. Other tests showed that differences in sampling methods and in processing operations may produce different interpretations of the level of Salmonella contamination of processed broiler carcasses.

1. Reducing Bacterial Contamination of Processed Chickens by Washings in Mixtures of Potassium Hydroxide and Lauric Acid. Chlorine continues to be the most widely used sanitizer in commercial poultry processing facilities in the U.S.; however, the EU does not allow the import of poultry sanitized with chlorine. Studies were conducted to examine the ability of solutions of potassium hydroxide/lauric acid to reduce the number of bacteria on the skin of processed broiler chickens. Findings indicated that repeated washing with potassium hydroxide/lauric acid reduced the number of bacteria recovered from broiler skin. The development of alternatives to current sanitizers used in commercial poultry processing may reduce the number of human foodborne diseases associated with poultry and open EU markets to U.S. poultry processors.

2. Microbiological Analysis of Poultry Carcass Rinsates, Scald Tank Water, and Scald Tank Foam. Cross contamination of broilers carcasses may occur during scalding operations if microorganisms can survive the high temperatures in scalder water and scalder foam. Studies were conducted to determine the number of bacteria present in scald water, in surface foam, and on broiler carcasses taken from scalder tanks of a commercial processing facility. Despite the high temperatures of water in the scald tanks, E. coli, Salmonella, and other bacteria were recovered from water, foam samples, and broiler carcasses. Results indicate that poultry processors and regulatory agencies should be aware that cross contamination of broiler carcasses may occur during scalding operation.

3. Comparison of Sampling Methods for Testing Salmonella Prevalence on Broiler Carcasses. Regulatory agencies in North America and Europe use different sampling methods for determining bacterial contamination of processed broiler carcasses. A study was conducted to compare the North American sampling method of examining samples of whole-carcass-rinses against the European method of examining rinsates of carcass neck skin. Results indicated that there was no significant difference in the number of Salmonella positive carcasses identified by the two methods when broiler carcasses were sampled before or after chilling. This data confirmed that regulatory agencies may consider using whole-carcass rinses or neck skin sampling for determining the prevalence of Salmonella contamination of processed broiler carcasses.

4. The Effects of Reusing Chiller Water on the Microbiological Characteristics of Processed Broiler Carcasses and the Chemical Characteristics of the Water. Poultry processing requires large amounts of water, but reusing water during some processing operations may reduce the amount of water used by poultry processing facilities. This study examined the effects of reusing treated chiller water to in chiller tanks to cool carcasses in a commercial poultry processing facility. Results indicated that chilling carcasses in reused water did not increase the level of contamination of the carcasses. Reusing water during chiller operations will help poultry processors to conserve this valuable natural resource.

5. Examining the Role of Water Hardness in the Ability of Water to Rinse Bacteria from the Skin of Processed Broiler Chickens. The characteristics of water used during poultry processing may play a major role on the microbial quality of processed chicken. Studies were conducted to determine the number of bacteria present on the skin of processed broiler washed in soft, moderately hard, or very hard water. Results indicated that fewer bacteria were recovered from samples rinsed in soft water than from skin rinsed in moderately hard or very hard water. These experiments indicate that poultry processors should monitor water hardness at their facilities and that processors can reduce contamination of chicken by reducing the hardness of water used in processing.

6. Determining Prevalence of Salmonella Enterica on Poultry Carcasses during Early Processing the – Serotypes and Antimicrobial Resistance Phenotypes. Salmonella continues to be one of the major human foodborne pathogens associated with poultry products. A study was conducted to determine the prevalence of this pathogen among broiler carcasses during initial phases of commercial processing and to determine the antimicrobial resistance patterns of the salmonella isolates. Results indicated that there is a high prevalence of Salmonella contamination of poultry carcasses during the early stages of processing. These data will provide processors and regulatory officials with information regarding the prevalence of Salmonella on carcasses during processing, and the antimicrobial resistance patterns associated with these food borne human pathogens.

7. Comparison of the Pass-Fail Probabilities of Two Salmonella Sampling Plans for Broiler Carcasses. Regulatory agencies in the U.S. and European Union (EU) utilize different compliance standards when monitoring commercial processing facilities for the prevalence of Salmonella. In this study, a statistical simulation was conducted to compare the Salmonella performance standards used for chilled broiler carcasses in the U.S. and in the EU. Results indicated that different results may be obtained when utilizing the different standards and that there may be interactions between differences in sampling methods and processing operations. These findings show that regulatory personnel and commercial processors in the U.S. and EU should be aware of differences in U.S. and EU standards when analyzing Salmonella compliance data.

8. Recovery of Bacteria from Featherless Broiler Carcasses after Forced Fecal Expulsion. During processing, some operations may force fecal material from the intestinal tract of the bird and contaminate the carcass with fecal bacteria that can cause foodborne diseases in humans. This study was conducted to determine if washing the carcasses could reduce the level of contamination after the carcasses were contaminated by the expelled fecal matter. Results indicated that unwashed carcasses were contaminated by high levels of fecal bacteria, but washing these carcasses reduced the level of contamination by Salmonella bacteria. Washing did not reduce although the number of E. coli and Campylobacter bacteria on the carcasses, however. These results demonstrate that carcass washing can be effective in reducing carcass contamination by some bacteria associated with fecal contamination.

9. Examination of the effect of Monolaurin on the Growth and Survival of Enterococcus and Salmonella Bacteria. Monolaurin, a derivative of the compound lauric acid, has been reported to possess the ability to inhibit bacterial growth. This research was conducted to determine if monolaurin could inhibit the growth of bacteria associated with poultry processing. Results indicated that although monolaurin was not able to kill bacteria isolated from poultry, it was able to reduce the growth rate of these bacteria. Due to limited ability of monolaurin to kill bacteria found on processed poultry, this compound possesses little potential as a sanitizer for use in poultry processing operations.

10. Phylogenetic analysis of Salmonella enterica serotype Enteritidis Isolates from Chicken Carcasses. Salmonella continues to be one of the major human foodborne pathogens associated with processed chicken meat. A study was conducted to identify various types of Salmonella isolated from broiler carcass rinsates, scald tank water, and scald tank foam taken from a commercial poultry processing facility. Salmonella isolates were identified by genetic analysis and the antimicrobial resistance pattern of the bacteria was determined. Results indicated that processing water and carcasses can be contaminated by several types of Salmonella. These findings will provide poultry processors and regulatory agencies with data that illustrates the prevalence of Salmonella during poultry processing, as well as information on the ability of Salmonella to resist the antimicrobial activity of several antibiotics.

11. Use and Validation of a Novel Molecular Serotyping Scheme to Identify Serotypes of Heat-Shocked Rough Mutant Salmonella Enterica. Processed broiler carcasses may be contaminated by different types of Salmonella. A study was conducted utilizing intergenic spacer region (ISR) analysis to identify mutants of Salmonella isolated from carcass rinsates, scald tank water, and tank foam taken from a commercial processing facility. Comparison of ISR analysis and traditional Salmonella identification methods indicated that ISR analysis can be used to accurate identify Salmonella isolates recovered from poultry processing environments. These experiments were the first application of this new technology to identify Salmonella mutants, and this research provided insight into how heat shock produced mutations in Salmonella serotypes. Findings from these studies will provide researchers and regulatory agencies with a new test to identify this important pathogen.

5.Significant Activities that Support Special Target Populations
Hosted 1 graduate student from Tuskegee University, 1 undergraduate student from the South Carolina minority participation (SCAMP) program, and 1 undergraduate student from the University of Georgia. The Tuskegee University student conducted research that was used to satisfy the research requirement for completion of their Master’s Degree, and the SCAMP student won first place among students who presented their research findings at South Carolina State University.

6.Technology Transfer

Number of Other Technology Transfer5

Review Publications
Northcutt, J.K., Mcneal, W.D., Ingram, K.D., Buhr, R.J., Fletcher, D.L. 2008. Bacteria recovery from genetically featherless broiler carcasses after forced cloacal fecal expulsion. Poultry Science. 87:(11) 2377-2381.

Hinton Jr, A., Holser, R.A. 2009. Role of water hardness in rinsing bacteria from the skin of processed broiler chickens. International Journal of Poultry Science. 8:112-115.

Hannah, J.F., Fletcher, D.L., Cox Jr, N.A., Smith, D.P., Cason Jr, J.A., Northcutt, J.K., Richardson, L.J., Buhr, R.J. 2009. Impact of Added Sand on the Recovery of Salmonella, Campylobacter, Escherichia coli, and Coliforms from Pre-Chill and Post-Chill Commercial Broiler Carcass Halves. Journal of Applied Poultry Research. 18:(2)252-258.

Liljebjelke, K.A., King, D.J., Kapczynski, D.R. 2008. Determination of minimum hemagglutinin units in an inactivated Newcastle disease virus vaccine for clinical protection of chickens from exotic Newcastle disease virus challenge. Avian Diseases. 52:260-268.

Roche, A.J., Cox Jr, N.A., Richardson, L.J., Buhr, R.J., Cason Jr, J.A., Fairchild, B.D., Hinkle, N.C. 2009. Contaminated Larval and Adult Lesser Mealworms, Alphitobius diaperinus (Coleoptera: Tenebrionidae)can Transmit Salmonella Typhimurium in a Broiler Flock. Poultry Science. 88:44-48.

Last Modified: 4/25/2014
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