Control of Foodborne Pathogens in Pre- and Post-Harvest Environments

Non-Technical Summary:<br/>
Foodborne illnesses are a major public health concern in the United States. Nontyphoidal Salmonella and Campylobacter spp. are the leading bacterial causes of foodborne illnesses in the United States. Live poultry is considered as an important reservoir for foodborne pathogens such as Salmonella and Campylobacter and that is why raw poultry meat is frequently contaminated with these pathogens. USDA Food Safety and Inspection Service (FSIS) has introduced new performance standards for poultry processing plants to reduce Salmonella and Campylobacter contamination in poultry carcasses. Listeria monocytogenes is another important foodborne pathogen, estimated to cause approximately 2,500 illnesses, 2,300 hospitalizations, and 500 deaths each year in the United States. Various outbreaks have been linked to consumption of ready-to-eat (RTE) meat and poultry products contaminated with L. monocytogenes. The recent USDA, FSIS data indicate that the prevalence of L. monocytogenes in RTE meat and poultry products has declined to 0.45% in 2008 but still its presence in RTE meat and poultry products is a significant health hazard due to its high case fatality rate and zero tolerance policy in RTE meat and poultry products. As poultry and poultry products per capita consumption increase annually, the risk associated with foodborne illnesses from Salmonella, Campylobacter and L. monocytogenes contaminated poultry products will also increase. In order to improve public health by ensuring food safety, there is a great need to decrease the prevalence of these pathogens in poultry products reaching the consumer table. Various pre- and post-harvest antimicrobial interventions have been approved and tested in poultry processing but none has resulted in total elimination of these pathogens in poultry products. Therefore, there is a critical need for additional interventions to use along with the existing preventive measures to further restrict the occurrence of these pathogens in poultry products at various steps in poultry processing.
<P>
Approach:<br/>
For the control of foodborne pathogens such as Salmonella, Campylobacter and L. monocytogenes during poultry processing, post-harvest processing and packaging, various USDA approved antimicrobials will be tested for their efficacy against inactivation, survival and growth of foodborne pathogens in fresh chicken carcasses, processed and RTE poultry products. Several novel GRAS antimicrobials will be tested for their effectiveness in reducing Salmonella and Campylobacter in raw and further processed poultry products. Sodium metasilicate is an alkaline GRAS antimicrobial and is approved as a marinade application by USDA, FSIS in poultry processing. Our recent findings show that sodium metasilicate completely inactivated Salmonella in vitro and reduced Salmonella populations significantly when used as marinade in chicken breast fillets. Sodium metasilicate and other USDA approved antimicrobials will be evaluated for their effectiveness in reducing the levels of Salmonella and Campylobacter contamination on broiler carcasses when applied as pre-chill and post-chill spray rinse and/or dips during processing of broiler carcasses; these antimicrobials will also be evaluated for its use in decontaminating pickers and other poultry processing equipment during first processing. Surviving Salmonella and Campylobacter populations after antimicrobial application will be recovered from carcass rinsates on XLT-4 agar and Campy-cefex agar, respectively. Novel antimicrobials such as lauric arginate, which has also been approved for use in ground poultry will be evaluated for their efficacy against foodborne pathogens in fresh cuts of poultry, ground and mechanically separated poultry meat. Cocktail mixtures of Salmonella and/or Campylobacter will be applied on intact skin surface of fresh cuts of poultry carcasses as well as ground poultry and then treated with lauric arginate to determine the surviving populations. Various lactic acid bacterial strains have been approved for use in RTE poultry products to control the growth and survival of L. monocytogenes. These strains will be tested for their bactericidal properties against L. monocytogenes under vacuum or modified atmosphere packaging for achieving reduction of L. monocytogenes in refrigerated stored RTE poultry products. Different RTE poultry products such as turkey bologna and turkey ham will be surface-inoculated with L. monocytogenes, treated with different concentrations and strains of lactic acid bacteria, packaged and stored under refrigerated conditions. At pre-set time intervals the surviving populations of L. monocytogenes will be enumerated to determine the anti-listerial effect of lactic acid bacteria. The survival and inactivation of foodborne pathogens will be evaluated by recovering the pathogens on selective media.
<P>
Progress:<br/>
2007/10 TO 2012/09<br/>
OUTPUTS: Despite the current use of pre and post-chill sprays/dips with a wide variety of antimicrobials during commercial poultry processing, Salmonella is frequently isolated from poultry products. It has become even more important to reduce the presence of Salmonella in poultry products after the introduction of new performance standards set by the USDA FSIS in 2010. In the present study, the antimicrobial effects of lauric arginate (LAE) against Salmonella in vitro and on chicken breasts were studied. LAE is an USDA approved novel antimicrobial compound and has been found effective against various foodborne pathogens. Salmonella cell suspensions were treated with 100, 200 and 400 ppm of LAE at 4C for 0 and 2h. The antimicrobial efficacy of LAE against Salmonella and mesophilic organisms was evaluated in raw chicken breast fillets. The effect of LAE treatments on pH and color of breast fillets was also assessed. Fresh skinless chicken breast fillets were inoculated with a four strain Salmonella cocktail (S. Enteritidis , S. Heidelberg, S. Kentucky and S. Typhimurium) and then treated with 200 and 400 ppm of LAE. The samples were stored at 4 C and analyzed on d 0, 1, 3, 5, and 7 for Salmonella, total aerobes, color and pH. <br/>PARTICIPANTS: Chander S. Sharma, Amanda Ates, R. Nannapaneni, P. Joseph, A. Kiess
<br/>TARGET AUDIENCES: Poultry processors, Further processed product processors, USDA FSIS and USDA NIFA
<br/>PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
<P>
IMPACT: Our findings revealed that LAE caused dose dependent reduction of Salmonella in vitro. Treatments of 200 ppm and 400 ppm of LAE exhibited bactericidal activity against Salmonella with no detectable surviving Salmonella after treatment at 2 h. In chicken breast fillets study, treating breast fillets with 400 ppm of LAE caused significant reduction (P < 0.05) in Salmonella populations on all days of analysis as compared to positive control except on day 3. The reductions in Salmonella after treatment with 400 ppm ranged from 0.7 to 1.0 log cfu/g. The reduction of Salmonella 400 ppm LAE treatment was maintained till d 7 of storage. Treatment of chicken breast fillets with 200 ppm also caused significant reductions of Salmonella populations on d 0, 1, and 7 of storage with level of reduction of 0.7 log cfu/g as compared to control on each day. No significant differences (P > 0.05) were observed for mesophilic counts in chicken breast treated with LAE and stored for 7 days although lower counts of total mesophilic organisms were seen as compared to control on each day of sampling. In addition LAE had no effect on the pH of chicken breast fillets. No significant treatment x day interactions (P > 0.05) were observed for instrumental meat color attributes (L*, a*, and b* values) of chicken breast fillets. These results indicate that surface application of LAE in chicken breast fillets significantly reduces Salmonella during refrigerated aerobic storage without negatively affecting the color of chicken breast fillets.