Keeping Pathogens Out: Step 1 of a Disease Prevention Strategy
Mark W. Bienhoff, DVM—Pathogen Control Team Leader, Kemin Industries
Infectious agents, or pathogens, are a threat to livestock and poultry health and even human health in some zoonotic situations. Pathogens that cause diseases also have significant economic implications, as well as negative effects on animal welfare. Keeping disease out of functioning production facilities is difficult due to the natural presence of pathogens, resulting in an endemic pathogen load. The goal of any biosecurity program is to (1) prevent the introduction of any infectious agent, (2) prevent or minimize dissemination of infectious agents within the facility and (3) minimize the impact of endemic pathogens that can cause subclinical disease.1 The purpose of this article is to summarize basic strategies and technologies that can be used to prevent disease from interring a livestock or poultry production facility.
Endemic, as well as pathogenic, contagious diseases can be transmitted between farms by various routes such as live animals, trucks and other vehicles, people, aerosols, fomites, wildlife and insect vectors.2 The frequency and/or contact patterns of these transmission routes can heighten the risk of disease introduction.3 To minimize these introductions, biosecurity routines must be put in to help reduce the probability of disease introduction and maintain the health and welfare of the production animals.
Importance of External Biosecurity
With the advent and increase of global travel and commerce, the possibility of an introduction of a foreign animal disease (FAD) into the U.S. livestock and poultry industries is enhanced. An Iowa State University study estimates potential revenue losses to the U.S. pork and beef industries from a foot-and-mouth (FMD) outbreak would run $12.8 billion per year, or $128 billion over a 10-year period. Additional losses to corn and soybean markets over the decade would also be sizable.4 Dedicated external biosecurity programs can help in preventing and containing the spread of an emerging epidemic disease.
Keeping pathogens out of a livestock or poultry production system is the first step for a disease prevention strategy and is considered one of the more cost-effective forms of health care. Published epidemiological modeling data would suggest that the most important indicator of biosecurity risk is the disease prevalence in the immediate area surrounding the production unit. It is well known that as disease prevalence/pressure rises, so does the risk for an outbreak. A suitable, isolated geographical location for a farm would be the most desirable. The second most critical factor is decreasing the number of contacts to potential outside pathogens. This can be accomplished through well-designed and implemented on-farm biosecurity programs. Third, the risk of disease introduction also depends on the infectious agent, as infectivity can vary dramatically between pathogens. These points support the importance of developing a biosecurity program, which accounts for the facility’s proximity to other animals, ability of the program to decrease outside pathogen contacts and recognize the characteristics of the pathogen to be avoided or eliminated.5
It is often said that disease enters into a facility on “two and four legs.” Additional biosecurity measures must be put in place to govern the movement of people and the animals/poultry coming into the clean production unit. The source and handling of the primary stock or birds must be monitored, and the disease status of placement animals fully understood. Transportation and movement should be provided with vehicles certified to be clean and properly sanitized.6
Kemin Pathogen Control Products and Programs
Kemin believes the initial environmental focus when drafting a comprehensive pathogen control program should include:
- Assessment of the external biosecurity procedures in place to reduce contact opportunities with outside pathogens and prevent their entry into the production facility.
- Standard cleaning (degreasers) and disinfection products, along with the accompanying procedures, should be used on premise surfaces. The goal is to provide a clean environment for livestock and poultry placement.
- Water sources, lines and tanks should be free of pathogens and biofilms removed.
- Livestock handling and transportation equipment must be cleaned and disinfected per accepted protocols. Proper drying of transportation vehicles must also be incorporated into the procedures.
- Biosecurity protocols for incoming materials, supplies and feeds must be put in place.
- Disinfection and sanitation of incoming materials and supplies is critical.
- Feed pathogen control products should be considered for nutrition programs, which minimize the risk of disease introduction from potential contaminated ingredients or mill manufacturing sites.
- Shipping and or transportation vehicles for incoming items must be verified as safe and clean.
As the livestock and poultry industries move toward disease prevention and control, increased emphasis must be placed on biosecurity programs to minimize the risk of pathogen transmission to healthy stock. Kemin promotes strong biosecurity programs that incorporate products and technologies which reduce contact opportunities and prevent pathogens from entering the production facility. Through development of on-farm protocols, which incorporate effective products and technologies, the goal of rearing livestock and poultry in a clean environment addresses our desire for optimum animal health and welfare.
- Seaman, J., Fangman, T. University of Missouri-Columbia Extension Publication #G2340; November, 2001; Biosecurity for Today’s Swine Operation.
- Mee, F.J., Geraghty, T., O’Neill, R., More, S.J. Bioexclusion from dairy and beef farms: Risks of introduction infectious agents and risk reduction strategies. Vet J. 2010;194:143-50.
- Rovid Spickler, A., Roth, J.A., Galyon, J., Lofstedt, J. Emerging and exotic diseases of animal. 4th ed. Ames; Centre for Food Security and Public Health Iowa State University; 2010.
- FarmandDairy.com, Keeping U.S. pork safe from disease. Date accessed, June 22, 2017.
- Lewerin et al. (2015). Risk assessment as a tool for improving external biosecurity at farm level. BMC Veterinary Research 11:171 DOI 10.1186/s 12917-015-0477-7.
- Morgan Morrow, W.E., Roberts, J.D. Biosecurity Guidelines for Pork Producers. NC State University Extension Service, ANS02-818S.
On-Farm Pathogen Control: A Priority for Today's Pig Farms
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.
Salmonella Remains Priority
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.
Biosecurity Is Linchpin
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.
Staff and Visitors Need Scrutiny
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:
- Develop and visibly post biosecurity standard operating procedures for animal caretakers and visitors.
- Limit visitors to those who have a reason to be there and only allow visitors when the producer is present.
- Consider the amount of downtime between visits to barns outside of the farm’s system of production as well to help mitigate disease transmission.
Isolate New or Returning Animals
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.
Clean and Sanitize Facilities and Equipment
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.
Keep Pig Transportation Equipment Clean
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.
Keep Wildlife, Rodents and Other Pests Away
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.
Don’t Overlook Feed
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.
Pathogen Prevention Requires Action
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.
Controlling Salmonella in Feed
Dr. Frank Jones—Professor Emeritus, University of Arkansas
Alexander the Great is thought to have died in 323 BC of a Salmonella infection and a similar fate is thought to have met Great Britain’s Prince Albert in 1861. Obviously, salmonellosis is an ancient disease caused by an organism that has probably always existed. That organism (Salmonella) continues to present challenges in the production of foods for man and animals.
Why is Salmonella so difficult to control? Perhaps there are two characteristics that make Salmonella such a challenge: persistence and adaptability. Salmonella can persist from months to years in a wide range of materials. As a result, Salmonella may be found nearly anywhere one wants to look. Once presented with favorable conditions, some organisms gradually begin to grow. However, Salmonella is capable of quickly adapting and growing in a wide range of conditions. This means that while high numbers of Salmonella (≥10,000 cfu/100g) have been found in feed, even the small numbers usually found in feed (≤10 cfu/100 g) present a potential threat. Thus, Salmonella contamination in feed is an issue that must be addressed.
First of all, it should be clearly understood that effective programs to control of Salmonella are MUCH more than simply the application of heat or chemicals to kill the microbe. Both heat and chemical inhibitors destroy a limited number of Salmonella cells and if cells remain after the application control method(s), feeds will (obviously) be contaminated. Therefore, it is important to keep the number of Salmonella cells present in the feed as low as possible. How do we keep Salmonella numbers low? By continuing attention to detail and sustained efforts to prevent contamination from entering the facility and work to reduce microbial multiplication within the plant. Overlooking either of these areas increases the likelihood that Salmonella will be found in the final product.
Although pelleting and extrusion are effective at Salmonella control, the processes are most effective when applied correctly. Effective control of microbes (including Salmonella) in feeds or pet foods using pelleting or extrusion involves: heat penetration, moisture, temperature, time and protection from recontamination.
The application of heat is most effective when all particles within the batch are heated to the target temperature for an adequate amount of time. Coarse particles will require more time for heat penetration than will fine particles. Therefore, grinding procedures can directly influence the effectiveness of pelleting or extrusion at microbial control. In most cases, feeds should be ground ≤ 700 microns prior to pelleting.
Moist heat is generally more effective at killing microbes (including Salmonella) than is dry heat. While the amount of moisture added to feed by steam conditioning is highly dependent on the formula involved, the goal should be ≥15% total moisture in the conditioned mash. Yet, too much water can be introduced by poor quality steam and the added moisture can encourage microbial growth in finished feeds. Consequently, it is important to ensure that high quality steam (i.e. ≥80%) is used in the pelleting or extrusion process.
The temperature and time required to kill Salmonella are inversely related. For example, the same number of Salmonella cells may be destroyed in feeds heated to 180°F for 40 seconds as in feeds heated to 170°F for 160 seconds. It is also important to remember Salmonella is not evenly distributed in feeds. Thus, small portions of feed may contain high numbers of Salmonella and harsher conditions will be required to destroy these higher numbers. Significant destruction of Salmonella in feeds generally starts at about 160°F and target temperatures of 180 to 185°F are generally recommended. While new equipment designs can allow manufacturers to keep feeds at these temperatures for ≥6 min., a minimum of 30 seconds should be maintained. However, even if pelleting or extrusion destroys 100% of the Salmonella cells present, recontamination of feeds following heat treatment can occur with relative ease.
As conditioned mash is pressed through dies, contamination can quickly be re-introduced via dust. This means the area around the pellet mill or extruder must be kept sanitary and dust free. Preventing dust from entering the cooler or drier is also crucial. In addition, it is important to ensure that coolers or driers produce a minimum of condensation since Salmonella can grow in these locations and contaminate feeds.
Chemicals offer some protection from recontamination and may, in some situations (e.g. mash feeds), be the primary means of controlling Salmonella in feeds. Yet, the heat from pelleting or extrusion has been shown to enhance the effectiveness of chemical inhibitors. Still, it is important to understand that, like pelleting or extrusion, chemical inhibitors are most effective when applied correctly.
To be effective, any compound added to feed must be evenly distributed, which obviously requires the use of equipment capable of delivering a homogeneous mix. Each particle must come in contact with the inhibitor for maximum effectiveness and each feed particle is potentially contaminated, thus a uniform distribution is especially important when using chemical inhibitors. A fine mist should be used to spray liquid products on feeds and dry products should contain very small particles so that as many particles of feed as possible are contacted for maximum effectiveness. It is also important to prevent the escape of dust and vapors from feed following the application of inhibitors since these materials can be irritating or toxic to feed manufacturing personnel.
Chemicals used to control Salmonella in feeds have primarily consisted of blends of organic acids (mainly formic and propionic acids) or formaldehyde. Although organic acids have been preferred as mold inhibitors, are naturally occurring, and are easily digested by almost all animals; inclusion rates of about 1% are required for significant kill of Salmonella. The use of such high levels of organic acids may be costly, corrosive to milling or feeding equipment, affect feed palatability, and interfere with utilization of vitamins. Consequently, organic acids are generally considered less effective at killing Salmonella than products containing formaldehyde. It should also be noted that formaldehyde is the only chemical approved by the Food and Drug Administration for the control of Salmonella in feeds.
Formaldehyde is effective against a wide range of microbes (including Salmonella) and it has long been used for preservation of feed ingredients in ruminant production. One reason for the effectiveness of formaldehyde is due to the fact that it forms vapors. When used in closed systems, formaldehyde vapors can effectively kill a wide variety of pathogens. Formaldehyde has also been applied to carriers such as grains, wheat feeds or woodchips to decontaminate the inaccessible interior surfaces of equipment. Yet the long-term effectiveness of formaldehyde may be limited when it is used in open systems or bins. Consequently, many commercial formaldehyde-based products also contain acids such as propionic acid or other antimicrobial compounds to reduce evaporation. Formaldehyde has also been used to treat certain feed ingredients that have been considered high risk (e.g. animal protein products) prior to shipment. Such treatments assist in protecting the ingredient from contamination during transit and provide some residual activity in feeds. However, formaldehyde use is not without risks.
Formaldehyde has been identified as a potential human carcinogen and workers may be exposed through the inhalation of vapors generated during the application process or as a result of dust from the treated feed. In addition, inhaled vapors may irritate the eyes, cause headaches, produce a burning sensation in the throat, result in difficulty breathing and trigger or aggravate asthma symptoms in feed mill personnel. While it should be noted that 90-95% of the formaldehyde applied to feed almost immediately binds to feed particles, quantities sufficient to cause human symptoms remain. Consequently, it is imperative that workers be protected from exposure.
Effective Salmonella control programs require continuing attention to detail and sustained effort in three broad areas:
- Preventing contamination from entering the facility
- Reducing microbial multiplication within the plant
- Killing the pathogen
Killing Salmonella in feeds usually involves the application of heat through steam conditioned pelleting or extrusion and/or the addition of chemical inhibitors. Controlling Salmonella via steam-conditioned pelleting or extrusion requires:
- Grinding feed ≤ 700 microns
- Total moisture in the conditioned mash of ≥15%
- Use of high quality steam (i.e. ≥80%)
- Temperatures of 180-185°F for a minimum of 30 seconds
- Protecting feeds from recontamination
Heat enhances the effectiveness of chemical inhibitors. Chemical inhibitors must be evenly distributed within the feed for maximum effectiveness. Chemical inhibitors are primarily made up of organic acids (mainly formic and propionic acids) or formaldehyde.
From a Vet's Perspective: An Interview with Amber Stricker, DVM
Amber Stricker, DVM—Veterinarian, Suidae Health & Production
With the fall season coming, what concerns do you have as a veterinarian? What are the most important points for producers as they prepare for the colder weather to come?
To me, maintaining pig health is critical and a big part of this is making sure pigs have a good environment to reduce stressors that make them more vulnerable to disease breaks. As fall approaches, it is important to have facilities in good repair to allow for optimum ventilation when the curtains go back up for the winter. The summertime is a good time to do a facility inspection and make notes of what items need to be replaced or repaired before heading into fall and winter. If these tasks are completed prior to the fall it makes winterizing barns a simpler process when the time comes. Along with this, biosecurity audits including on-farms, truck washes and feed mills should be done annually to identify areas where improvements can be made. Although biosecurity is important to focus on year-round, it is well known that the colder months of the year pose more of a risk to the health of the swine herd.
In the news, we have seen an increase in PEDv instances this summer, mainly in Canada. What do you think this means for the U.S. industry and what can we learn from these cases?
I believe this is a reminder to the industry that we cannot let our guard down, even during the summer months. This is why our recommendation for biosecurity and pathogen control protocols do not change throughout the year. If it is important for the winter, it is important for the summer. We must remain disciplined in our approach to biosecurity at all times.
From your perspective, what has been the biggest change in the last 5 years regarding the management of animal health?
The biggest change that food animal veterinarians have seen, in my opinion, is in regards to the continued pressure to reduce the use of medically important antibiotics. This has been a major test as the industry works to find the best practices to work around these new challenges. Today, we veterinarians need to be more diligent in our recommendations, making sure we are managing animal health in a manner that is best for the pigs and the people who consume our pork. I think we are doing this pretty well in the swine industry, however, I believe we can do even better. For example, I believe efforts to drive diet costs down have led to some health management challenges, especially as it relates to post-weaning diarrhea. Often times these challenges are addressed with the strategic use of antibiotics along with management strategies to reduce subsequent production losses, however, this is something we need to continually re-evaluate as we look at taking a more preventative approach.
As a veterinarian, I am passionate about the use of preventative medicine to reduce the need for antibiotic usage. Each health challenge presents a mystery to be solved and too often the case is closed without really finding the guilty party. Swine farmers who see the value in spending extra time to get to the root cause is where the true value of working with a good veterinarian lies. This is the part of medicine that I really enjoy and where I encourage us to spend more time.
On that note, what do you think is the future of Antibiotic Free (ABF) swine production?
In my personal opinion, I don’t know that we will ever get to No Antibiotics Ever (NAE) in swine production. I just don’t think it is realistic. In human medicine, many children would not make it past infancy without the aid of antibiotics, even when being cared for in the best environments. In addition, if you look at the increases in the cost of production for producers who go ABF, it is significant; much more than what the poultry industry reports. As the supply of ABF/NAE increases, the premiums at the meat counter, as compared to conventionally produced pork, are narrowing. I do believe there will be continued demand for ABF/NAE pork by consumers, but unless we find a way to reduce the cost of production to ensure a profitable margin, the industry will have a difficult time making this work. If the consumer is willing to pay, the market will grow and has the potential to be profitable, but the consumer must be willing to pay.
Preventative medicine and immunity: What is the future of vaccines?
With enhanced focus on preventative medicine, access to safe and effective vaccines is key. However, even with the best vaccines on the market, the reality of the situation is that we do not raise pigs in a bubble. Caretakers must do their best to provide a low stress environment with good ventilation and access to proper feed and clean water in order to maintain a high-health pig. Exposure to pathogens must be avoided through good biosecurity measures and management practices that allow for pigs to thrive.
Final thoughts or recommendations from a veterinarian:
Times are changing and the days of using antibiotics as the sole health management strategy are over. Now more than ever, a team approach is needed for the best animal health management. Many producers are underutilizing their veterinarians and not fully capturing the value they can provide. Routinely working with your veterinarian to identify root causes of reoccurring health challenges and develop disease prevention strategies will pay dividends. Together we can do even better.
Taking Animal Health and Welfare to the Next Level
Mark W. Bienhoff, DVM—Pathogen Control Team Leader, Kemin Industries
Kemin Industries Vision
Introduced in 1998, Kemin Industries adopted a worldwide strategy summarized by their vision: We strive to improve the quality of life by touching half the people of the world every day with our products and services. The Kemin mission, as a global manufacturer of innovative nutrition and health solutions, is to meet the needs of the world’s growing population. With this growth will come a greater need for reliable access to sufficient quantities of affordable, nutritious and safe food. The United States Department of Agriculture coined this term, “food security.”1 Kemin believes continuous change is a way of life and sees needed livestock and poultry production changes to meet this new demand. The production of meat, milk and eggs for human consumption will not only need to increase but will also need to be more efficient. Production of animals in a healthy environment improves their welfare, which is a key driver for efficient livestock and poultry production. Kemin has established a Pathogen Control Team, which provides comprehensive environmental pathogen control products, technologies, services and programs that will decrease disease risk as well as increase the volume and improve the efficiency of global food production.
The production of meat, milk and eggs for human consumption is coming under increased pressure as the global human population continues to increase. Sporadic, acute disease outbreaks, caused by common pathogens or the introduction of new pathogens, increase food product costs and are risks to global nutrition. The University of Minnesota Swine Health Monitoring Project showed that with the entry of Porcine Epidemic Diarrhea Virus (PEDV) into the U.S. pork industry, the number of sows farrowed decreased by 0.25%, the number of pigs saved per litter dropped by 3.2% and the number of pigs harvested dropped by 5.2 million during the period of September 13, 2013, to August 14, 2014.2 In poultry, the outbreak of High Pathogenic Avian Influenza (HPAI) virus in 2014-2015 caused the death of an estimated 50 million birds, mostly egg-laying hens.3 Both of these acute outbreaks show diseases can have fast and dramatic effects on profitability and food production.
Also of interest are the effects of ongoing, endemic disease in production facilities. Dr. Robert Desrosiers pointed out at the 2015 American Association of Swine Veterinarians (AASV) meeting, “We have not gotten rid of any of the emerging pathogens of the last 40 years.” He continues with, “…adding diseases without eliminating any is not a good long term strategy.”4 It has been estimated that Porcine Respiratory and Reproduction Syndrome Virus (PRRSV) results in annual losses to the swine industry of around $664,000,000.5 Ongoing losses from both of these endemic diseases can have dramatic effects on profitability and food production.
Of even more concern are the possible effects of transboundary or foreign animal diseases entering the U.S. livestock and poultry industries. At the 2017 annual meeting of the AASV, Dr. Jeff Zimmerman noted that detection of African Swine Fever Virus (ASFV), Classical Swine Fever Virus (CSFV), or Foot-and-Mouth Disease Virus (FMDV) would devastate the U.S. pork industry in a matter of hours. Rendleman and Spinelli (1999) estimated the 1992 U.S. dollar cost of ASFV at $4,500,000,000 to $5,445,000,000.6 Because this study took place back in the 1990’s, the amount would be grossly low if repeated today. Transboundary disease introduction requires risk management programs to be put into place to prevent the entry and spread of disease in today’s global market place.
The Importance of Biosecurity and Pathogen Control Programs
It is well known that infectious agents are a threat to livestock and poultry health and at times, human health. With today’s intensive production conditions, prevention is the most viable and economically feasible approach to the control of infectious agents. Biosecurity and pathogen control plans are utilized by livestock and poultry producers to reduce disease transmission through contact with infected animals, people, pests, manure, insects, trucks, air, water, feed and other vectors.7 It is known that manufactured feed can transmit pathogens into a production facility infecting the animals, causing disease, decreasing productivity and negatively affecting animal welfare.8Salmonella serotypes potentially found in animal feeds have been shown to spread to humans; therefore, causing zoonotic outbreaks of foodborne illness.9
Biosecurity procedures at the herd level are put in place to reduce the probability of disease introductions into the herd. It should be noted that following the Swedish ban of antimicrobial feed additives in 1986, rising problems with infectious disease in pig production facilities were mainly controlled by improving external and internal biosecurity.10 External biosecurity involves assessing the prevalence of disease in the immediate geographical area surrounding the farm and minimizing the frequency of outside, between-farm contacts. Internal biosecurity involves minimizing the spread of disease among animals within the facility and the prevention of transfer of zoonotic agents to people visiting the farm or consuming their food products.
Development of Kemin Pathogen Control Products and Programs
In livestock and poultry production facilities, the diversity of microbes, combined with their ability to evolve and adapt to changing populations, environments, practices and technologies, creates ongoing threats to animal health and challenges efforts to prevent and control diseases. Ongoing assessments and disease surveillance is needed for producers to know what pathogens are in their immediate area. Kemin believes there are three (3) environmental focus areas when drafting a Comprehensive Pathogen Control Program:
- External biosecurity procedures must be put in place to reduce contact opportunities with outside pathogens and prevent entry into the production facility. You must prevent the pathogens from entering your facility.
- Identify and implement interventions to reduce infectious disease. This involves cleaning and disinfecting products within the production facility to lower pathogen load. This may involve vaccines and controlled antibiotic treatments used strategically under Veterinarian direction. You must control and decrease pathogen load within the facility.
- Prevent pathogen zoonosis to employees working within the livestock and poultry production unit and to humans consuming the end harvested food products. You must control possible pathogens from leaving your facility.
Kemin Pathogen Control Team Objectives
In this era of continued disease threats, antibiotic controls through Veterinary Feed Directive (VFD), Food Safety Modernization Act (FSMA) regulations imposed on nutrition programs and reduced overall antibiotic usage, preparing for efficient and safe livestock and poultry food production will take new tools and strategies. Animal health and welfare programs are changing from traditional diagnosis and treatment tactics, to prevention and control. Through direct work with livestock and poultry producers, the Kemin Pathogen Control Team can assess your production facility, identify areas that could be problematic, make recommendations and provide prevention strategies for your system. These strategies will focus on products and programs which will lower and control your production facility’s pathogen load. By addressing animal health and welfare through comprehensive pathogen control programs, we believe we can help meet the Kemin mission to improve the quality of life by touching half the people of the world every day with our products and services.
- https://www.ers.usda.gov/topics/food-nutrition-assistance/. Accessed on March 14, 2017.
- www.nationalhogfarmer.com/animal-well-being/economic-impacts-pedv. Kneeskern, Samantha. “Economic Impacts of PEDV.” National Hog Farmer, November 03, 2015. Accessed on March 18, 2017.
- www.cidrap.umn.edu/news-perspective/2015/08/report-finds-12-billion-iowa.... “Report finds $1.2 billion in Iowa avian flu damage.” Center for Infectious Disease Research and Policy, August 18, 2015. Accessed on March 10, 2017.
- Desrosiers, R. 2015. Emerging diseases: The past and the future. Proc 46th Ann Meet Am Assoc Swine Veterinarians. Orlando, Florida, pp. 519-537.
- Holtkamp, D., J. Kliebenstein, E. Neumann, J. Zimmerman, H. Rotto, P. Yeske, T. Yoder, C. Wang, C. Mowrer, and C.A. Haley. 2013. Assessment of the economic impact of porcine reproductive and respiratory syndrome virus on United States pork producers. J Swine Health Prod 21: 72-84.
- Zimmerman, J. 2017. Swine medicine in the 21st century: Immovable object meets unstoppable force. Proc 48th Ann Meet Am Assoc Swine Veterinarians. Denver, Colorado, pp. 14-19.
- Desrosiers, R. "Transmission of swine pathogens: Different means, different needs." Animal Health Research Reviews 12.01 (2011): 1-13.
- Davies, P. R., et al. "The role of contaminated feed in the epidemiology and control of Salmonella enterica in pork production." Foodbourne Pathogens & Disease 1.4 (2004): 202-215.
- Hald, Tine, et al. "Human health impact of Salmonella contamination in imported soybean products: A semiquantitative risk assessment."Foodbourne Pathogens & Disease 3.4 (2006): 422-431.
- Lewin et al. 2015. Risk assessment as a tool for improving external biosecurity at farm level. BMC Veterinary Research 11:171 DOI 10.1186/s 12917-015-0477-7.
Feed Biosecurity: Oxymoron or Global Paradigm Shift?
Scott Dee, DVM, MS, PhD, Dipl:ACVM—Director, Pipestone Applied Research
What a difference a few years makes! Prior to the porcine epidemic diarrhea virus (PEDV) epidemic in 2013-2014 across North America, no one seriously considered feed as a potential vehicle for pathogen transmission. However, there is now a growing body of scientific evidence strongly suggesting that feed and feed ingredients may be risk factors for the spread of PEDV at both the domestic, and the global levels. In addition, research in progress is also starting to evaluate whether other viruses, possibly foreign animal disease pathogens that are currently not native to North America, i.e. foot and mouth disease, African swine fever, to name a few may also have the ability to “travel the world” via contaminated feed.
Should these theories prove to be true (and I believe they will), global agriculture will need to experience a significant paradigm shift and there will be a requirement to develop protocols of “feed biosecurity” across all agricultural industries, including the processing of grain, the manufacturing feed and feed ingredients, in order to deliver a safe product to our ruminant and monogastric livestock populations. Please remember that the companion animal profession already experienced a very similar issue; how many of pets became sick or died following the consumption of food imported from China that was contaminated with melamine?
What are the solutions? How do we manage this risk? Unfortunately, at this time answers are not readily available; however, we are hard at work. The critical first step would be to conduct properly designed studies to identify feed ingredients that have the ability to promote pathogen survival. Next, studies need to be conducted that simulate the transport of products from China to the US under conditions that represent actual transport times and environmental conditions. Based on these data, I would envision that the next steps could involve several options, such as the adaptation of biosecurity practices at the level of the feed mill and the delivery truck, along with the application of mitigants to neutralize any existing viruses and thereby protect feed as it moves from place to place. Finally, and perhaps most importantly, the entire mindset regarding ingredient sourcing may need to experience a dramatic paradigm shift. Specifically, we need to start making decisions on the sourcing of ingredients from countries that are free of foreign animal diseases. In other words, we need to make decisions that are based on health, instead of than price.
Now, I understand these ideas are easy to talk about, but challenging to implement. However, I believe that once our industry is provided with scientifically-sound data on the identity of actual risk and how to manage it, we will put our best foot forward and let science dictate the decision-making, not economics and politics. In the end, I foresee a market-driven response to this issue that will demand a high level of safety across the products we feed our animals along with a high level of scrutiny across our processes and protocols. I would also be hopeful that our governmental agencies would step up, providing leadership and resources to facilitate ongoing research and the application of the outcomes at the high-risk sites, such as countries of origin, ports of entry and feed mills across the country. This strategic, collaborative approach is our best chance at changing the concept of feed biosecurity from an oxymoron to a strategic process that is science-based and actually has a chance at protecting US agriculture.
The Chicken Parts Performance Standard: Opportunities Ahead
Ashley Peterson, PhD—Sr. VP of Scientific and Regulatory Affairs, National Chicken Council
Consumer preference has changed with regards to the chicken they are purchasing. Buying a whole chicken at the grocery to take home and prepare is not as common as it used to be and, in fact, only represents about ten percent of the chicken products U.S. consumers are putting in their shopping carts. This is important information for the U.S. chicken industry as well as United States Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS), as these two groups share a common goal, which is to reduce the prevalence of Salmonella and Campylobacter on chicken products. Knowing what our consumers are purchasing allows both the industry and FSIS to focus efforts on those products.
Since the original performance standards for young chicken carcasses were established, the broiler chicken industry has made considerable progress in driving down the prevalence of both Salmonella and Campylobacter – a four-fold decrease – as evidenced by FSIS data on whole bird rinses. But what has that really done to impact public health? Despite a significant drop (a 9 percent decrease) in human illnesses from Salmonella in recent years, salmonellosis remains a serious concern in the U.S. leaving the industry and the federal government searching for answers.1 So there is an open question: will increased efforts by both the industry and FSIS to address Salmonella and Campylobacter on poultry parts impact public health? Only time will tell.
As background, in early 2012, FSIS collected nearly 2,500 chicken parts from federally-inspected chicken establishments in order to determine a prevalence baseline for both Salmonella and Campylobacter on chicken parts. FSIS determined that the prevalence of Salmonella and Campylobacter on chicken parts were 26.3% and 21.4%, respectively.2 Even before a performance standard was developed for chicken parts, the industry began researching various interventions, equipment design and application techniques in both first and second processing with the goal of reducing the prevalence of both Salmonella and Campylobacter on chicken parts. In a collaborative manner, chicken processors have been working closely with experts, equipment suppliers, antimicrobial suppliers, FSIS and others to explore opportunities, challenges, and potential solutions—which has led to the improved foods safety results we are seeing today.
In February 2016, FSIS published the new chicken parts performance standard in the Federal Register - “New Performance Standards for Salmonella and Campylobacter in Not-Ready-to-Eat Comminuted Chicken and Turkey Products and Raw Chicken Parts and Changes to Related Agency Verification Procedures: Response to Comments and Announcement of Implementation Schedule.” This document finalized reduction standards for Salmonella (15.4%) and Campylobacter (7.7%) on raw chicken parts and not-ready-to-eat (NRTE) comminuted chicken products. The new pathogen reduction performance standards target the products that are commonly consumed in the U.S. – specifically breasts, wings, legs and comminuted poultry – and specify the maximum number of samples out of 52 total samples that may test positive while still meeting the performance standard.3 Although the standard is not strictly regulatory in nature, it is intended to encourage pathogen reduction through categorizing establishments into three tiers (Category 1, 2 or 3) based on how closely they meet the standard. The notice additionally announced that FSIS would change its’ sampling program from a “set-based” approach of testing a given number of product samples in a given number of consecutive days, to a routine, “moving window” approach, in which FSIS would test product samples weekly to obtain an average performance metric.
The new standards took effect on July 1, 2016, along with the first set of establishment-specific category posting for whole birds. Along with the new standards came an unexpected change in the sampling program, with FSIS switching from the buffered peptone water (BPW) traditionally used for all prior sampling, to new, neutralized buffered peptone water (nBPW) based on substantial public pressure and an Agricultural Research Service study contending that the previously-used BPW may not adequately neutralize commonly-used antimicrobial treatments. This change in sampling technique raises significant questions about the scientific validity of comparing performance standard samples collected using nBPW with the baseline samples collected using traditional BPW. The impact that the nBPW may have on the prevalence of Salmonella and Campylobacter on carcasses, parts and comminuted chicken products is still being discussed within FSIS.
With all of the changes and challenges around the verification testing for Salmonella and Campylobacter, the natural question is how these factors may impact the publicly available category results. Since the implementation of the new performance standards and the change to nBPW, the percentage of all establishments meeting Category 1 standards for Salmonella on whole birds has dropped from approximately 91 percent to 68 percent, with the percentage of large establishments meeting Category 1 standards dropping from 95 percent to 74 percent. Similarly for chicken parts, the percentage of all establishments meeting Category 1 standards for Salmonella has dropped from 42 percent to approximately 38 percent, and large establishments meeting Category 1 standards has dropped from 50 percent to about 41 percent.4 (Data are current as the FSIS aggregate dataset for the period November 8, 2015, through January 28, 2017). The percentage of all establishments, and large establishments, meeting Category 1 standards for Campylobacter on whole birds and chicken parts has remained largely unchanged.
Preventing consumer exposure to foodborne pathogens will continue to be the goal of the industry and FSIS, and it requires the teamwork of FSIS, the broiler industry, and consumers to achieve the best results. Though the pathogen performance standard for chicken products serves as a starting point for encouraging process control, there is clear room for improvement in this program. More accurate indications of process control may be achieved by consistent and scientifically rigorous sampling. The broiler chicken industry will continue to develop innovative methods to control Salmonella and Campylobacter during processing, and to work with FSIS to produce a safe, wholesome chicken product.
- Centers for Disease Control and Prevention. Morbidity and Mortality Weekly Report: Incidence and Trends of Infection with Pathogens Transmitted Commonly Through Food – Foodborne Disease Active Surveillance Network, 10 U.S. Sites, 2006-2013. April 18, 2014. 63(15); 328-332.
- United States Department of Agriculture, Food Safety and Inspection Service, Office of Public Health Science, Microbiology Division. The Nationwide Microbiological Baseline Data Collection Program: Raw Chicken Parts Survey. January 2012 – August 2012. https://www.fsis.usda.gov/shared/PDF/Baseline_Data_Raw_Chicken_Parts.pdf.
- New Performance Standards for Salmonella and Campylobacter in Not-Ready-to-Eat Comminuted Chicken and Turkey Products and Raw Chicken Parts and Changes to Related Agency Verification Procedures: Response to Comments and Announcement of Implementation Schedule. 81 Fed. Reg. 7285 (February 11, 2016).
- United States Department of Agriculture, Food Safety and Inspection Service. Salmonella and Campylobacter Verification Testing Program Monthly Reports: Aggregate Salmonella and Campylobacter Categorization for Young Chicken and Turkey Carcasses, Raw Chicken Parts, and NRTE Comminuted Poultry Establishments (Nov. 8, 2015 – Jan. 28, 2017). https://www.fsis.usda.gov/wps/wcm/connect/e6b2e91e-d9d6-4a58-82cc-3e832e256490/establishment-categories-aggregate-201702.pdf?MOD=AJPERES.
Stewardship of Antibiotics Begins with Improved Biosecurity
Tom Marsteller, DVM—Technical Service Manager (Swine), Kemin Industries
What is the stewardship of antibiotics programs on your farm? Google “stewardship of antibiotics” and you might be surprised to find most of the web-based information is related to human health care. Effective September 2014, Presidential Executive Order 13676 directed the secretary of Health and Human Services to establish the Presidential Advisory Council on Combating Antibiotic Resistant Bacteria (PACCARB), in consultation with the secretaries of Defense and Agriculture, on methods to combat antimicrobial resistant bacteria.2 PACCARB will communicate new methods to prevent bacterial infection through metrics, tracking, hygiene and biosecurity for both human and animal health. One method health care providers are striving for is to prevent health care associated infections.3 PACCARB has documented that preventative measures (biosecurity) are key in health care facilities to keep antimicrobial resistance in check.
The animal health industry has now fully implemented FDA Guidance Documents 152, 209 and 213 rules and regulations, effective January 2017.4 These regulations prohibit the use of medically important antibiotics for growth promotion, but still allow their use as therapeutics in the animal food industry. The medically important antibiotics are not to be administered to animals through feed or water without veterinary oversight. It took many years for these voluntary rules and regulations to be fully implemented, with the desired effect of decreasing the burden of antimicrobial resistant bacteria in livestock that could potentially spread to humans. The consumer trusts the producer and veterinarian to apply antibiotics responsibly: proper dose, length of use and withdrawal period followed.5 It behooves the industry not to lose this consumer trust and follow the new January 2017 guidelines.
Just as significant as the new antibiotic use rules, changes are ongoing within the animal industry to prevent diseases from ever occurring. Eliminating worrisome diseases in livestock has led to a decreased need for antibiotic use for prevention, control or treatment of animal diseases. Many producers and veterinarians in the swine industry have taken steps toward improving antibiotic stewardship on farms by eliminating PRRSV and Mycoplasma hyopneumoniae in production groups of animals.6,7,8 Preventing vertical spread of these two diseases from the sow to offspring is accomplished by selecting breeding stock that is negative to these two diseases and/or proper herd closures and treatment of mycoplasma infected sows.9 After the sow herd is negative, the offspring can be grown until market, and the need for antibiotic use to control these two respiratory diseases is decreased significantly. Preventing the spread of these two pathogens by horizontal transmission could not have been accomplished without a significant investment in world class biosecurity. Those investments include: routine diagnostic monitoring, single source pig flow, increased biosecurity at all facilities, closure of breeding herds including multiplication, monitoring boar health, installing incoming air filters in sow and boar housing, heated truck washes, all-in all-out production, three-site system design and proper location of facilities to prevent internal and area spread of pathogens.10 Why were these decisions made to manage health in a dramatically different manner today versus the past? Consumers, retailers, non-government organizations, processors and packers continue to encourage the animal production industry to change their behavior on antibiotic use.11 While animal well-being and disease treatment are still paramount for a safe food supply, consumer pressure will continue to encourage livestock producers to decrease their practice of routine antibiotic use. Prevention of diseases and top notch biosecurity is the cornerstone to decreased antibiotic use in the livestock industry.
With the introduction of porcine epidemic diarrhea virus (PEDV) to the U.S. swine industry in 2013, producers and their health management teams have taken a high interest in how this virus is transmitted. It is now known that PEDV can survive in feed and contaminated feed can create PEDV in naïve pigs.12 The swine industry is n aware of the importance of biosecurity at the feed mill with respect to PEDV.13,14 We can’t let our biosecurity guard down in any part of the animal production facilities with respect to disease prevention.
Societal demands to improve the health and well-being of animals will continue to increase in the future. Managing the health of livestock requires increased diligence in biosecurity and the prevention of vertical and horizontal spread of diseases. Animal health professionals will need to be vigilant using disease diagnostics and employing all the tools at their disposal to rear animals in an environment which allows them to perform at their full genetic potential. Realistically, it continues to be a very competitive marketplace for food production. Whoever can meet the demands of the customer with the optimal cost of production will see their business grow.
- Biosecurity definition: procedures intended to protect humans or animals against disease or harmful biological agents. www.Google.com. Accessed on March 1, 2017.
- https://www.hhs.gov/ash/advisory-committees/paccarb/meetings/upcoming-meetings/january-25-2017-public-meeting/index.html#. Accessed on March 1, 2017.
- PACCARB Meeting Summary, Fifth Public Meeting PACCARB, Department of Health and Human Services, January 25, 2017.
- https://www.fda.gov/AnimalVeterinary/SafetyHealth/AntimicrobialResistance/JudiciousUseofAntimicrobials/. Accessed on March 1, 2017.
- http://www.pork.org/production-topics/antibiotics-resource-center/on-farm-resources/pork-industry-guide-to-responsible-antibiotic-use/. Accessed on March 1, 2017.
- Schwartz M. The cost of Mycoplasma hyopneumoniae in growing pigs. Allen D. Leman Conference 2015.
- Dee S. PRRS Eradication: Why does it fail? ISU Swine Disease Conference for Veterinarians 2002, pgs 63-70.
- Donovan T. PRRS Control and eradication in a production system. Allen D. Leman Conference 2011, pgs 151-156.
- Holst S, Yeske P, Pieters M. Elimination of Mycoplasma hyopneumoniae from breed-to-wean farms: A review of current protocols with emphasis on herd closure and medication. J Swine Health Prod., 2015; 23(6)321-330.
- Desrosiers R. Emerging diseases: The past and future; AASV Proceedings 2015, pgs 519-538.
- NRDC. A Case Study. Going mainstream: Raising meat and poultry without routine antibiotics use. December 2015, CS:13-03-C.
- Dee S, et al. An evaluation of contaminated complete feed as a vehicle for porcine epidemic diarrhea virus infection of naïve pigs following consumption via natural feeding behaviors: proof of concept. BMC Vet Res. 2014; 10:176. Doi:10.1186/s12917-04-01769-9.
- Cochrane RA, et al. Feed mill biosecurity plans: A systematic approach to prevent biological pathogens in swine feed. J. Swine Health Prod., 2016; 24(3)154-164.
- Greiner LL. Evaluation of the likelihood of detection of porcine epidemic diarrhea virus or porcine delta coronavirus ribonucleic acid in areas within feed mills. J. Swine Health Prod., 2016; 24(4)198-204.