For the most part, U.S. broiler and turkey processors have done a good job of reducing the percentage of Salmonella-positive carcasses found in post chill checks. Processors have employed various chemical sprays, rinses and dips along with treatment of the water in the chillers to rinse off, damage or kill enough Salmonella cells to stay in front of the performance standards established by the U.S. Department of Agriculture Food Safety and Inspection Service. Poultry processors have shown significant reductions in Salmonella tests since the post-chill carcass performance standards were first established.
Unfortunately, the decline in the incidence of Salmonella in post-chill carcass sampling is not mirrored by a decline in the number of human salmonellosis cases attributed to poultry consumption. I realize that we could have an attribution problem, but we could just as easily have a problem with trying to correlate a post-chill whole carcass tests with Salmonella levels on ready-to-cook finished products. After all, the percentage of broilers actually sold at retail as whole birds was less than 8 percent of total pound the last time I looked, and it is probably even less for turkeys outside of the holiday season. Most ready-to-cook chicken and turkey in the U.S. are sold as parts, skin-on or skin-less, or ground product.
The FSIS plans to establish new Salmonella baselines for ground turkey and chicken products and will establish baselines for parts for the first time as well. Some sampling data for parts at the retail level show Salmonella prevalence much higher than what would be expected given the industry’s post-chill carcass sample results. This leads to the questions of why and what to do about it?
At the Poultry Federation Salmonella Summit, held March 26-27, 2013, I heard a couple of theories that might explain the disconnect between the post-chill carcass Salmonella results and the results for parts. Dr. Shelly McKee, associate professor, poultry science, Auburn University, said that many poultry processors do not employ antimicrobial agents in the prechiller. McKee expressed concern that moisture picked up in the prechiller may be bringing a bacterial load along with it and that this bacteria is not all killed in subsequent chillers. She suggested that processors should look at what is going on in their prechiller and adjusting how it is being used to make sure that moisture picked up during chilling doesn’t wind up increasing bacterial lodes when the carcasses are cut-up. “You need to treat birds before the pre-chiller or put your antimicrobials in the pre-chiller,” she said. The use of post-chill antimicrobial sprays and dips show promise for reducing Salmonella on parts prior to grinding or traypacking, according to McKee. Antimicrobial treatment of poultry parts after the carcass is cut-up is just one more hurdle for Salmonella control, a continuation of the rinsing off of Salmonella that starts with brushes before the scalder and continues with various rinses, inside outside bird washers and finally in the chiller. The rinses and dips all fit with the outside-in theory of Salmonella contamination where Salmonella contamination is on the “outside” surface of the carcass and it can be removed, and the internal muscle tissues and organs of the bird are not contaminated with Salmonella.
Dr. Scott Eilert, vice president, food safety, quality and regulatory, Cargill Value Added Meats-Retail, said that in research the company has conducted bone-in-parts used to make ground turkey are associated with higher Salmonella levels than parts that are ground after the bone has been removed. “The battle is not just fought on the surface of the bird; we still don't fully understand the internalization of Salmonella and maybe Campylobacter,” Eilert said. He said that it is important to look at which serotypes of Salmonella can colonize internal organs and tissue of the bird and which organs or tissues become contaminated. He referred to Salmonella in internal organs as Salmonella that was internalized in the bird. There was a lot of discussion in the question and answer sessions regarding the relative importance of Salmonella in the bone marrow of leg bones of turkeys. Eilert’s view that internal sources of Salmonella in the carcass are contaminating parts and ground products did not seem to be widely held, but industry sources report that many turkey processors have gone back to only grinding boneless parts for making ground turkey.
I suppose it would be simpler for the poultry industry if reduction of Salmonella on parts really did come down to better bacterial control in the pre-chiller, but is anything ever that simple? My experience has been that if it involves living organisms, whether poultry, people or bacteria, nothing is simple or easy. The Salmonella Summit provided a good opportunity for poultry companies to learn from each other and advance the goal of producing safer products.