A global look at Salmonella and Campylobacter control for poultry

The simplistic way of describing the two primary approaches to Salmonella control for ready-to-cook poultry products is the European approach, which is to eradicate Salmonella in live production, and the U.S. approach, which focuses on application of physical, chemical and thermal interventions in processing to reduce Salmonella incidence.

Okeefe T Headshot

The simplistic way of describing the two primary approaches to Salmonella control for ready-to-cook poultry products is the European approach, which is to eradicate Salmonella in live production, and the U.S. approach, which focuses on application of physical, chemical and thermal interventions in processing to reduce Salmonella incidence.

The problem is that there isn't very much that is simple about Salmonella control, and now that Campylobacter control is also part of the puzzle, it appears that successful control of Salmonella and Campylobacter will require joint efforts on the farm and at the processing plant.

While U.S. poultry companies have taken the lead in investigating and implementing chemical interventions in processing to reduce Salmonella and Campylobacter incidence on whole carcasses, parts and meat, they have also worked to reduce the prevalence of these organisms on the feed, breeder farm, hatchery and on the meat bird farms.

Objectives and standards

The original objective of Salmonella control programs in poultry was improved bird health. Once the Salmonella serotypes that negatively impact bird health and performance were controlled, the emphasis was shifted to control Salmonella serotypes that affect human health. There have been two primary efforts made to improve human health through Salmonella control in poultry, to reduce or eliminate known human pathogenic strains of Salmonella from poultry products or to reduce the incidence of all Salmonella strains. In the U.S. the FDA has targeted specific Salmonella strains, primarily Salmonellaenteritidis but also Salmonella Heidelberg, for eradication from table egg farms. While serotype data is being collected for Salmonella samples taken from poultry meat in the U.S. the USDA's performance standards for Salmonella don't differentiate between serotypes.

Salmonella control outside the US

Brazil and New Zealand are two poultry producing countries that have chosen to follow the USDA model for Salmonella control in poultry meat. While Brazil is the world's third largest producer of chicken meat, New Zealand processes just 85 million chickens per year. Both countries sample carcasses post-chill using the USDA technique and the object is reduction of all Salmonella serotypes.

The Salmonella control approach in New Zealand and Brazil has been primarily focused on preharvest control. Roy Biggs, food safety and QA manager, Tegel Foods Ltd., New Zealand, said, "You really need to get rid of Salmonella on the farm, there is really no point in waiting and trying to fix it at processing. If you break the cycle on farm, you don't get much entering processing."

Dr. Maria Teresa Destro, associate professor, food microbiology, University of São Paulo, Brazil, said the Brazilian government has established regulations for meat bird and breeder farms. She told the audience at the International Association of Food Protection's annual meeting that minimum standards have been set for biosecurity. Items such as farm location, maintenance of roads and external grounds, the type of construction and size of buildings, drainage from farms, ventilation of houses and access to the farms are all addressed. There are gates and fences required around breeder farms and these have disinfectant sprays at the gates. "Green belts," a vegetative buffer strip of shrub-like trees, are also required around grandparent housing.

Many of the good manufacturing practices employed in Brazil in live production of broilers mirror those in the U.S., but Destro did point out some differences. For instance, in Brazil feed delivery trucks are disinfected between deliveries, dedicated trucks are used to deliver breeder feed, and feed samples from all deliveries must be taken and held for four months.

Salmonella vaccinations

In Brazil and New Zealand, breeder flocks are vaccinated for Salmonella, as are grandparent flocks in Brazil. Destro said breeders in Brazil are tested to look for possible Salmonella contamination, and Salmonella positive individuals are euthanized, but she did not say what percentage of birds are tested.

Biggs said breeders in New Zealand are tested for Salmonella and are euthanized if they remain Salmonella positive after treatment. About 10 percent of New Zealand's broilers are raised free-range, and Biggs said these are the only meat birds that are vaccinated for Salmonella.

Concrete floors are standard for meat bird and breeder farms in Brazil and New Zealand. Breeder farms are operated as all-in all-out facilities in Brazil. Breeder farms are completely cleaned and disinfected between flocks, and there is a minimum of two weeks downtime required in Brazil. Meat bird farms are not required to completely clean out each flock in Brazil, but if they are not, the litter must be composted in between flocks.  All meat bird houses in New Zealand are completely cleaned out and disinfected between flocks.

Destro said that feed is withdrawn from the birds in Brazil a minimum of 24 hours prior to slaughter and that some producers acidify the drinking water when they withdraw feed. Feed withdrawal is only eight hours in New Zealand. In Brazil, flock records go to the plant along with the birds, and these include parent flock identification, flock mortality information, medications administered and the withdrawal dates.

In Brazil, all meat bird flocks are tested for Salmonella one to two weeks prior to slaughter. Salmonella-positive flocks are processed at the end of the day at a lower line speed under what Destro called "strict control," and their meat is used for cooked products.

Processing interventions

Because of EU requirements, Destro said the only chemical intervention used in Brazilian poultry plants is chlorine. All reprocessing for fecal contamination is done online according to Destro, but bird washers have been allowed at the end of the evisceration line since 2011.

All live haul cages and trucks are cleaned and disinfected after each use in both Brazil and New Zealand.

Salmonella results

Biggs said a 1996 New Zealand government survey found that 17 percent of broiler carcasses were positive for Salmonella at retail. Salmonella control programs instituted by poultry companies in New Zealand have resulted in low Salmonella incidence on post-chill carcasses, with only 0.4 percent of carcasses positive for Salmonella in the first quarter of 2013 (see Table 1).

The Brazilian Health Surveillance Agency sampled 2,710 frozen broiler carcasses at retail between 2004 and 2006 and found that 82 carcasses (4 percent) were positive for Salmonella. The most current post-chill carcass sampling data for Brazil presented by Destro showed a 6.4 percent incidence of Salmonella-positive carcasses in combined government and industry sampling from October 2003 to July 2008 (see Table 2). Half of Brazilian broiler processing plants had Salmonella incidence rates on carcasses of less than 5 percent (see Table 3).

The Salmonella incidence rate in USDA broiler and turkey carcass samples is lower than what was reported for Brazil but not quite as low as for New Zealand (see Graph 1).

Campylobacter results

Preharvest Salmonella interventions have been able to deliver relatively low Salmonella incidence rates on carcasses at the end of the chiller in countries like Brazil and New Zealand where chemical interventions are not utilized as extensively as they are in the U.S. But the same chemical interventions that reduce Salmonella numbers in the processing plant also reduce Campylobacter. Unfortunately, preharvest Salmonella interventions appear to have little impact on Campylobacter incidence rates.

Sharon Wagener, manager, production and processing animal products group, New Zealand Ministry for Primary Industries, said that in spite of low Salmonella incidence rates on poultry in New Zealand, the country had the dubious distinction of being the Campylobacter capital of the world in 2006 when they had 15,783 human cases (380 per 100,000 of population). The number of cases had been on a steady upward trajectory since 1980 when only a few hundred cases had been reported. She said that some research showed the main contributor to these cases was poultry.

Late in 2006, New Zealand started a Campylobacter control program and became the first country to mandate targets for Campylobacter incidence rates on poultry. After discussions between New Zealand Food Safety Authority and industry, a requirement was established for processors to employ an intervention that provides at least a two log reduction in Campylobacter numbers of broiler carcasses.

Biggs said the Campylobacter load has been reduced by one half log since the control program was initiated and that the percentage of broiler carcasses that are positive for Campylobacter has been reduced from 60 percent in 2007 to below 40 percent in 2013. Most importantly, the rate of human illnesses attributed to Campylobacter in New Zealand has been cut by more than 50 percent in the same time frame.

Biggs said reductions were seen in Campylobacter on carcasses as a result of replacing old evisceration equipment, the initiation of multiple carcass sprays, and use of chiller treatments other than chlorine, like peroxyacetic acid. He said they have tried organic acids and oligosaccharides in the feed, but did not see large reductions. He said that with currently available technologies Campylobacter control will most likely take place in the plant, not on the farm.

The USDA began publishing the results of Campylobacter sampling of broiler and turkey carcasses over the past year (see Graph 2). The multi-hurdle approach adopted by U.S. processors has yielded incidence rates of Campylobacter-positive broiler and turkey carcasses of less than 6 and about 2 percent, respectively, in the first four quarters for which data has been published, the second quarter of 2012 through the first quarter of 2013.

Page 1 of 33
Next Page