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United States Department of Agriculture

Agricultural Research Service

Research Project: INTERVENTIONS AND METHODOLOGIES TO REDUCE HUMAN FOOD-BORNE BACTERIAL PATHOGENS IN CHICKENS
2012 Annual Report


1a.Objectives (from AD-416):
The purpose of the Poultry Microbiological Safety Research Unit is to further reduce or eliminate bacterial pathogen contamination in poultry operations and the following objectives are to:

1. Assess the effectiveness and further development of bacteriocins (anti-bacterial peptides) and bacteriophage by in vitro bacterial growth inhibition in culture and in vivo experimentation via challenge in chickens.

2. Reduce bacterial populations in chicken litter by monitoring poultry houses for bacterial pathogens carried by chickens during use of intervention technologies. Decontamination techniques, such as in-house foam applied disinfectants will be examined for reduction of Campylobacter spp., Salmonella spp., Clostridium perfringens and Listeria monocytogenes.

3. Improve cultural methods for Campylobacter spp. in poultry in further support of FSIS needs, including the improvement of recovery. Use microarray expression analysis under various cultural conditions to identify nutrients necessary for optimal growth, colonization and culture of Campylobacter spp.


1b.Approach (from AD-416):
New antimicrobial agents will be developed that are usable by the poultry farmer on a large scale to reduce Campylobacter spp. and salmonellae by applying in feed at the appropriate times before slaughter. Also, new means for the drug-free production sector to control clostridial disease without relying on antibiotics are the major expected approaches of Objective 1. Providing a science based source of data to better dispose of spent poultry litter without major energy or financial inputs is the approach for Objective 2. A more reliable and quantitative method to routinely culture Campylobacter spp. from food and environmental samples is the approach of Objective 3.


3.Progress Report:
Scalding and chilling profiles impact on carcass and breast meat yield in broilers was evaluated. Flocks were either hard (60ºC for 1.5 min) or soft (52.8ºC for 3 min) scalding. Following defeathering the carcasses were either air chilled (0.5ºC for 120 min) or immersion chilled in water and ice (0.5ºC for 40 min). Post-scald defeathered-eviscerated carcass weight was 1% higher for soft-scalded carcasses (74%) than for hard scalded-carcasses (73%). During air chilling carcasses lost weight resulting in post-chill carcass yield of 73% for soft-scalded and 71% for hard-scalded carcasses, a difference of 1.7%. During water chilling carcasses gained weight resulting in post-chill carcass yield of 78% for soft-scalded and 76% for hard-scalded carcasses, a difference of 2%. Breast meat yield was greater by 0.7% for soft-scalded carcasses (17.6% for air-chilled and 17.9% for water-chilled) than for hard-scalded carcasses (16.8% for air-chilled and 17.3% for water-chilled). Soft scalding carcasses resulted in a 1% higher post-scald-defeathered eviscerated carcass yield over that for hard scalding carcasses, which persisted following chilling as a small but significant 0.7% higher breast meat yield. Broiler breeder chicks were placed in an experimental broiler breeder rearing facility and were fed free choice for 2 weeks. A total of 600 pullets were divided into 3 groups (200 pullets each) and fed one of the following programs:.
1)Skip-a-day;.
2)Every day in the feeder; or.
3)every day on the litter floor. All pullets were fed daily after light stimulation for egg production at 21 weeks of age. The development of the immune system was monitored by measuring bursa, spleen and thymus weights (as a percentage of body weight) and histopathology between 2 and 17 weeks of age. Innate immune responses were measured by determining the colonization rate in various tissues after oral challenge with S. Enteritidis. S. Enteritidis in spleen and ceca ranging between 10 and 68% at 22 and 65 weeks of age in the birds fed every day on the litter was lower compared with the skip-a-day and every day in the feeder fed groups. The results obtained suggest that feeding broiler breeder pullets on the litter may contribute to decreased rates of S. Enteritidis colonization after challenge.


4.Accomplishments
1. Scalding operation protocols for hard and soft scalding of broilers. Electroporation-spray, spraying with levulinic acid (3%) and SDS (2%), and spraying with bromine (500mg/L) failed to significantly lower carcass skin Salmonella and Campylobacter from challenged breast skin samples compared to treatment with chlorine (20 ppm). Chemicals that have been approved for direct food use are contimously evaluated for potential use in the commerical processing plant to reduce and/or eliminate Salmonella and Campylobacter.

2. Naturally occurring Campylobacter in a broiler rinsate can survivie in cold storage. While Campylobacter are thought to be fragile, Agriculture Research Service scientists in Athens, Georgia demonstrated that Campylobacter survives after long-term frozen storage (20 months) at 4°C or - 23°C in rinsate alone. Therefore frozen raw foods that are naturally contaminated with Campylobacter may still pose a potential health hazard even after 1-2 years in a freezer.


Review Publications
Hannah, J.F., Wilson, J.L., Cox Jr, N.A., Richardson, L.J., Cason Jr, J.A., Buhr, R.J. 2011. Horizontal transmission of Salmonella and Campylobacter among caged and cage-free laying hens. Avian Diseases. 55:580-587.

Hannah, J.F., Wilson, J.L., Cox Jr, N.A., Richardson, L.J., Cason Jr, J.A., Buhr, R.J. 2011. Colonization of a marker and field strain of Salmonella Enteritidis and a marker strain of Salmonella Typhimurium in vancomycin pretreated and non-pretreated laying hens. Avian Diseases. 55:588-592.

Berrang, M.E., Meinersmann, R.J., Cox Jr, N.A., Cray, P.J. 2011. Application of chlorine dioxide to lessen bacterial contamination during broiler defeathering. Journal of Applied Poultry Research. 20(1):33-39.

Richardson, L.J., Cox Jr, N.A., Buhr, R.J., Harrison, M.A. 2011. Isolation of Campylobacter from circulating blood of commercial broilers. Avian Diseases. 55(3):375-378.

Last Modified: 12/19/2014
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