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BIOSECURITY ON PIG FARMS Dr. Brian Hardy NutriVision Inc. BiosecurityAll pig farmers are now part of a pork chain and the chain is only as strong as the weakest link. In today’s market there is an ever increasing concern over food safety and consumers are taking more interest in where their food comes from and how it is produced. The words “pre-harvest” and “post-harvest” are being used more frequently to describe live animal production and post-slaughter respectively. There are more techniques used routinely “post-harvest” to protect meat products from food spoilage organisms and potential pathogens that may cause food poisoning in humans than there are used on the farm. In the future this will need to change. Development of “trace-back” systems will be used to identify the source of any food borne pathogen involved in a zoonoses situation. In Denmark, for example, pig farms are currently put into one of three categories regarding Salmonella risk. This allows for segregation and slaughter of high-risk animals separately from low risk animals. High-risk farms are visited to identify the most likely source of contamination and corrective measures implemented. The term “Biosecurity” is widely used, but most dictionaries do not carry a definition for this word. A good definition may be “measures imposed to protect a biological system from attack by potentially harmful microorganisms that can reduce the level of health of man and animals.” It is recommended that all farms conduct a critical review of the measures in place to prevent disease entering their operation. Application of HACCP (Hazard Analysis of Critical Control Points) procedures will help to identify areas of greatest risk to the business and allow for development of preventative strategies. Staff training is essential for them to gain a full understanding of biosecurity and the importance to minimize risk of infection. Regular audits need to be made with appropriate check lists (similar to those seen in restrooms) to monitor the practical implementation of the preventative actions imposed. Biosecurity measures should be used to protect the farming system from both external entry of pathogens and also internal transfer between different parts of the farm. Biosecurity enhances animal performance, minimizes disease, reduces medication costs and overall improves quality assurance of the pork chain (Table 1).
Pig farmers often assume that they have adequate biosecurity procedures because they have a “shower in/shower out” facility. Some of the most obvious sources of infection receive inadequate attention on many farms. These include the following: A) Dirty sows are moved from the gestation barn to the clean and disinfected farrowing room. The skin, hair and feet can carry bacterial infections as can the gastrointestinal tract. B) No hand protective barrier, either physical or chemical, is used when the staff process litters of pigs, running the risk of spreading infection from one litter to another. C) In the farm office it is important to clean the computer keyboard, the telephone, the shower and toilet and the lunchroom, including all surfaces with an appropriate bactericidal product. D) There should be a disease prevention disinfectant area at all times at entrances to the farm for all vehicles and foot dips for staff between all rooms and barns on the farm. E) In the food industry audit procedures are used to check on the sanitizing procedure. Farms should consider using a long-lasting bactericidal coating product including a fluorescent dye that can be detected by “black light.” This is similar to the detection of mold on corn. Vectors Many routes exist for disease to gain entry to the farm. These include animate objects, such as, live pigs, dead pigs, people, birds, rodents, flies, and semen. Also inanimate objects, such as, buildings, pens, transport, feed, air, water, clothing, tools and equipment, packaging materials, food and drink items. Examples of vectors, critical control points, preventatives and audit points are shown in Table 2. Pathogens The main food-borne zoonotic pathogens in pigs are Salmonella, Yersinia, Arcobacter, Campylobacter, Toxoplasma and Eschericia Coli. There are other pathogens that are more detrimental to livestock health and performance and include PRRS, Swine Flu, Eschericia Coli, Mycoplasma, Lawsonia, Circovirus and Erysipelas, etc. Veterinary consultants can give advice regarding identification of the most likely vector for each organism and the probable effect on the respiratory, digestive, reproductive system or skin. Antimicrobials Some of the most commonly used antimicrobials are alcohols, halogens (chlorine), silver, mercury, phenols, peroxide, quaternary ammonium compounds, ethylene oxide, chlorhexidene digluconate, peracetic acid, and glutaraldehyde. Many of the sanitizers and disinfectants used on the farm today include one or other of these materials. Conclusions Use of a proactive biosecurity program based on HACCP principles has several benefits in the pork chain. It gives an internal message to staff and company owners that animal health is important. It gives an external message to visitors and suppliers to meet biosecurity standards. It sends a favorable message to the media about concern for food safety. It obtains recognition from customers and prospects that you are in the food business.
Fedorka-Cray et al. (1995) Alternate routes of invasion may affect pathogenesis of Salmonella Typhimurium in swine. Infection and Immunity. 63 (7) 2658-2664 Hardy B. (1999) A world without growth promoters. In Concepts in Pig Science, 1st Annual Turtle Lake Pig Science Conference. p 53-70. Ed. TP Lyons and DJA Cole. Pub. Nottingham University Press. Anon (2002) PRRS submissions on the rise; transmission route unclear. Feedstuffs, March 4th Kavanagh N.T. (1999) Control of food borne pathogens in pigs. Biotechnology in the feed industry, Proceedings of Alltech 15th Annual Symposium. Ed TP Lyons and KA Jacques. Pub. Nottingham University Press. Wray C. and Davies R.H. (1996) A veterinary view of Salmonella in farm animals. PHLS Microbiology Digest. 13 (1), 44-48 ARTICLE CONTRIBUTED TO “ANIMAL TALK” PUBLISHED BY NOTTINGHAM NUTRITION INTERNATIONAL. August 2002. Close
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