Salmonella and the Pennsylvania Poultry Industry

Shelley Rankin
Director, Salmonella Reference Center, University of Pennsylvania

In 1988, British Health Minister Edwina Currie provoked outrage in the agricultural industry when she stated that “Most of the egg production in this country, sadly, is now affected with salmonella.” What many didn’t realize is that she was correct! Salmonella enteritidus (which has a rodent reservoir) emerged in poultry in the 1970’s and was deemed a major concern for food safety. By the early 1990’s, the number of outbreaks in the United States had risen rapidly and while the number of outbreaks has declined since, salmonella continues to be present in eggs.
The egg industry in the U.S. is big, with 446 million layer birds producing 7.6 billion eggs annually. Iowa is the largest producer with 53 million layer birds. Pennsylvania is the fourth largest producer with 26 million layer birds. Pennsylvania responded to this public health threat by launching the Salmonella Enteritidis (SE) Pilot Project. In 1992-1993 the project cultured 226,966 eggs 1,269 samples from layer house environments such as the manure pits so as to determine the prevalence of salmonella enteritidus. The results showed that 38 percent of the layer houses and 23 percent of the eggs were positive.
This led to the Pennsylvania Egg Quality Assurance Program (PEQAP.) It is a voluntary industry program intended to minimize SE contamination of eggs. The Pennsylvania Department of Agriculture provides oversight, technical advice and financial assistance. More recently, the producers who participate in the program have covered the costs associated with lab testing. By participating, these producers are assuring the public that they are taking every reasonable precaution to assure the safety of their eggs. Pennsylvania was the first state in the nation to institute steps to reduce the risk of SE with an effective flock testing and management program.
PEQAP does not guarantee eggs to be free of SE but it does assure commitment of the producer to implementation of those management and monitoring practices most likely to prevent SE contamination. Best management practices include populating houses with chicks from SE-Clean breeders, practicing effective rodent control, cleaning and disinfecting between flocks and vaccination. They also include egg washing, egg refrigeration and bio-security.
The program’s environmental testing requires that manure samples are taken at four different stages of the production cycle. If there is a positive manure test, then egg testing is required and any positive egg pool requires diversion of all the eggs produced to pasteurization. None of those eggs reach the table egg market. From January 1992 to December 2009, PEQAP tested 2.4 million eggs and 97,000 environmental samples. As in many endeavors, the price of success is hard work.