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Food safety and livestock health concerns continue to grab news headlines. Possibly the most common and costly food borne illness affects both pigs and humans, salmonellosis. This includes infection with Salmonella choleraesuis, as well as other Salmonellae, like S. typhimurium. In a recent NAHMS survey, nearly 95% of farms were positive for at least one type of Salmonella, and 35% had more than one.

To combat Salmonella following an outbreak from fresh pork in 1993, Denmark started a national Salmonella reduction program. This was done to safeguard both their people and the valuable Danish pork export market. The goal of the program was simple — reduce the level of Salmonella in pork. Today, the program has met its goal of less than 1% of fresh pork contaminated with Salmonella, versus over 8% in the US. Marketing their success has helped with Denmark's exporting success. It also helps their producers be more profitable!

Impact on productivity

Infection with Salmonella can have obvious clinical effects, such as mortality due to S. choleraesuis septicemia (blood infection). Diarrhea from S. typhimurium is another common clinical presentation in nursery and finishing pigs (See the September 2000 Insight for more on enteric diseases of growing pigs). Like many diseases though, visible losses are often just the tip of the “lost production” iceberg.

Sub-clinical infection with Salmonella has been shown to reduce gain by as much as 40 pounds per pig space per year; chronic exposure to Salmonella can reduce gain and lower throughput in finishing barns even without mortality. Iowa State University researchers discovered this when looking at performance and health information from typical midwest finishing barns. When other factors were controlled, farms with high levels of Salmonella exposure produced 8 pounds less pork per square foot of finishing barn space. Performance responded to measures that reduced Salmonella exposure.

Reducing the impact

Salmonella reduction takes a concerted effort that focuses on all aspects of production. Pig flow, sanitation, vaccination are among the key factors in reducing exposure in commercial systems. Productivity gains similar to those above have been demonstrated when Salmonella exposure was reduced. By using process audits to expose weak points, risky production practices can be identified. With a combined effort, production can improve and Salmonella exposure can be reduced.

More information

Nielsen, et al. A new Salmonella surveillance and control programme in Danish pig herds and slaughterhouses. Proceedings 4th Salinpork. 2001

Baum D. PhD Thesis. Iowa State University

Nolan et al. Use of Process Behavior (SPC) Charts for the purpose of continuous improvement in swine production. Proceedings of the American Association of Swine Veterinarians. March 2000.

Application

Economic Benefits

Reducing Salmonella levels associated with improved performance.

Reducing levels of Salmonella exposure from Level 3 (>35% of pigs positive) to Level 1 (<10% positive) was associated with a significant increase in production of pork per pig place. Researchers at Iowa State University demonstrated an increase of 8# pork per square foot of finisher space in low Salmonella barns. Whether directly due to Salmonella reduction, or a by-product of management changes, was not known. However, the results have been repeated in other farms. Reducing Salmonella pays!