On Farm Control of Salmonella in Pork

Food quality and safety have become focal points in food production and pork is no exception. Foodborne diseases caused by pathogenic bacteria are increasingly publicized in the media. Salmonella infection due to contaminated food products is one of the major causes of human illness and responsible for substantial economic losses worldwide. Each year there are millions of people infected with Salmonella through contaminated food products and thousands of them die from the disease. In the U.S. alone the annual economic costs of human illness due to Salmonella infections are 2.3 billion dollars. Data from the U.S. on foodborne disease outbreaks suggests that 6-9% of foodborne Salmonella infections are associated with pork and pork products. In Denmark, pork and pork products were reported to be responsible for 10-15% of the total Salmonella infections.

Salmonella are bacteria, which exist everywhere in the environment. "Attempting to unravel the epidemiology of Salmonella infection in both humans and animals continues to provide employment for many health professionals. There is little to suggest that a ‘magic bullet’ is on the horizon." (R. Ashley Robinson, August 1996). To date, more than 2,300 Salmonella serotypes have been identified. Most of them are not harmful to humans. S. typhimurium DT104 is the one that poses the most threat to human health. It is believed that complete exclusion of pathogenic Salmonella from animal populations is neither realistic nor possible. So the challenge, across the entire farm-table continuum and within each of its segments, is to identify the optimal mix of control measures to deliver the most cost-effective reduction in risk of human illness.

Consumers are demanding food safety assurances, not only during slaughter, processing, and preparation, but also at the farm level. Therefore, producing high quality and wholesome pork and pork products for both domestic and international markets is the responsibility and priority of the whole pork industry. On farm pork production is the beginning of the pork supply chain and, therefore, pork producers have a special and important role to play in producing safe pork. While there is no silver bullet for on farm Salmonella control a combined approach is the best way to deal with this unwanted organism in pork.

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How to Control Salmonella at the Farm Level

Incoming pigs

Any animal entering your swine unit has a potential risk of introducing Salmonella to the herd. The good production practice (GPP) is to reduce the sources of animals entering the unit to as fewer as possible. This can be done by purchasing hogs from 1-2 suppliers.

More attention should be paid to breeding stock. Both Swedish and Danish’s Salmonella control program emphasize monitoring of suppliers of replacement breeding stocks. Buying replacement breeding stock from CQA certified breeders and asking for Salmonella status of the breeding herds are highly recommended.

Use quarantine procedures in the unit for the incoming animals.

Feed

Feeds could be contaminated with Salmonella, therefore, appropriate process control and decontamination steps in feed mills are essential to avoid dissemination of contaminated feeds to pig herds. Purchasing feeds or feed ingredients from a mill with Quality Assurance is a good and useful production practice.

Vehicle: Any vehicle used for transporting feed stuff cannot be used for transporting hogs unless it is thoroughly cleaned, washed, disinfected and dried.

Feed storage area should be clean, dry, and free from rodents and animal feces.

Water

Water is also a potential source for introducing Salmonella to hogs especially when it is contaminated with feces. Water should be tested for Salmonella on a regular basis.

Mixing Pigs

Results from several studies demonstrated that mixing pigs could increase the prevalence of Salmonella due to the spread of Salmonella from positive to negative animals so that mixing pigs should be minimized.

Sick Pigs

Sick pigs are more prone to shedding Salmonella from their feces than healthy pigs, therefore, they should be separated and kept apart to prevent Salmonella cross-contamination.

Removing Dead Pigs

Dead hogs should be removed from the pen and/or barn immediately and disposed of properly to prevent the spreading of Salmonella and other diseases.

Washing Hands

Employees should wash their hands thoroughly using warm water and soap after treating/handling sick animals. The importance of proper hand washing is often overlooked.

Equipment

All the equipment used for mixing, storing, distributing feeds should be cleaned on a regular basis.

Any vehicle used for transporting feed cannot be used for transporting hogs unless it is thoroughly cleaned, washed, disinfected and dried.

Barns

Keep barns clean, dry and well maintained.

Remove manure from pen floors on a regular basis; provide adequate ventilation.

Clean and disinfect barns after each lot to break the vertical transmission cycle.

Visitors

All visitors must follow proper protocol - exchange their shoes and clothes with clean boots and coveralls and wash their hands and equipment before entering into the barn. Equipment, coveralls and boots should be cleaned and disinfected immediately after use. This will help prevent Salmonella introduction from other positive herds.

Loading Areas

Loading areas should be cleaned and disinfected after use.

Rodent, Fly, Pet and Insect Control

Effective rodent, wild bird, fly, insect and pet control programs play an important role in Salmonella control. All of the above are potential Salmonella carriers.

Hygiene, Sanitation and Overall Environment Cleanness

Good hygiene and sanitation programs such as emptying and cleaning of feeders, water drinkers and overall environment cleanliness are essential to an effective Salmonella control program.

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