Dr. Steve Larsen—Assistant Vice President of Science and Technology, National Pork Board
Providing safe, wholesome food is a pork producer's most important responsibility. Ensuring food safety is a complex undertaking that requires awareness of the role everyone plays in the food chain. On the farm, many factors can affect the safety of pork, which is why today's farms use a wide variety of technology and techniques to minimize food safety threats. These modern practices have vastly improved today's pork in terms of safety and quality, but improvements can always be made.
For the pork industry, Salmonella is the foodborne pathogen of primary concern. Like any other food, pork can be contaminated during any stage along the production and supply chain. Over the past few years, there has been increasing regulatory pressure for producers to implement on-farm control measures to reduce and/or eliminate foodborne pathogens, specifically for Salmonella.
Although there is no silver bullet for on-farm control of Salmonella, the best approach is a combined control strategy that will keep your pigs healthy and safe. Safe pork starts with healthy pigs, which is why on-farm biosecurity strategies are critical to Salmonella prevention and why maintaining a close working relationship with a veterinarian is of utmost importance.
The goal is always to keep healthy pigs healthy, rather than having to treat sick pigs after the fact. That's why biosecurity is absolutely essential to improving pre-harvest pork safety. Biosecurity is simply a combination of management practices designed to prevent the introduction and transmission of diseases and disease-causing agents into a herd.
People who come onto a farm site can transfer pathogens on their body and clothing to the pigs. Employees, visitors and others who may come onto the premises need to follow biosecurity protocols.
Vehicles also can carry unwanted pathogens that could infect pigs. To protect the health of the herd, limit the number of visitors and vehicle traffic. Specifically, you should:
Because pig-to-pig contact is a primary way diseases typically get spread, it's wise to follow strict biosecurity and isolation protocols to reduce potential spread of pathogens. Temporarily isolating all incoming animals is a sound biosecurity practice to follow. Also, isolating any pigs that may return to a farm means keeping a new pig separate from animals already on the farm for a set amount of time. During this time, be sure to carefully look for signs that a pig may be infected before going back into the herd.
Proper sanitation of the facility and equipment means keeping it free of dirt and debris as much as possible. Organisms that cause disease in pigs (bacteria, viruses and parasites) can survive in different types of materials. Cleaning, disinfecting and drying facilities is a critical part of daily sanitation and a key component of a biosecurity plan that can keep the level of disease-causing pathogens to a minimum.
Transporters of pigs, feed and other supplies and equipment to the farm need to be aware of the role that transportation can play in disease prevention. Organic matter (e.g., shavings, manure, etc.), water, mud or snow carrying diseases on boots, clothing, tires, undercarriages, trailers, shovels, winter panels, sorting panels and clothing can infect healthy pigs. Therefore, biosecurity steps should be taken to keep live-animal vehicles, feed trucks and any other support equipment clean.
Wildlife, birds, rodents, feral swine and other pests can readily transmit many diseases and compromise biosecurity. Limiting exposure to these animals with good fences and other physical barriers, along with a regular pest-control strategy, are vital to reducing this exposure to commercial pigs.
While unexpected, feed can serve as a vector for certain diseases that affect both swine and human health. Care should be taken when handling, processing and storing feed and feed ingredients in order to limit the possibility of contamination by rodents and other pests. When in doubt, send proper feed samples to a testing facility and/or back to the feed supplier for testing prior to feeding.
Once Salmonella is present in a production system, which is very common, increased efforts must be made to reduce its persistence, spread and proliferation. While total on-farm eradication of Salmonella is not feasible, maintaining control efforts can certainly control and reduce the prevalence of it.
As an industry, we will likely see more pressure from regulatory agencies for on-farm pathogen control over time. This is another reason investment in pre-harvest research is needed so we can identify the best strategies to consistently reduce or eliminate Salmonella across the range of pork production types.
For now, producers and their veterinarians must remain committed to the ongoing task of risk mitigation with biosecurity at its core. Although it's not a perfect solution, it remains the best way to reduce the spread of a pathogen such as Salmonella—a worthy goal as domestic and international demand for U.S. pork remains on an upward path, even with record production.
Figure 1. Schematic on Salmonella sources in pork production