March 31, 2014
US steps up scrutiny in pig feed over PEDv
United Statesscientists and regulators are stepping up their scrutiny of the nation''s pig feedwhile investigating the spread of PEDv in their pork industry.
With a dearth of solid leads, investigators are exploring whether something in pig feed could be a conduit for porcine epidemic diarrhoea virus (PEDv), which has spread to 27 states and killed millions of young pigs since it was first identified in the United Stateslast April. One focus of the inquiry is porcine plasma, a widely used feed ingredient made from the blood of slaughtered hogs and fed to piglets.
Scientists say the virus, one of the most devastating diseases to afflict United Stateslivestock in years, is fatal only to young pigs, and poses no threat to human health or food safety. But it has rapidly increased costs for major hog-farm operators, such as Smithfield Foods Inc. and Maschoffs LLC, as prices for replacement pigs have soared to new highs.
The disease threatens to curb United States pork supplies in coming months and raise costs for big meat processors, such as Hormel Foods Corp. and Hillshire Brands Co., as well as retailers and consumers, analysts say.
The number of new confirmed cases of the PEDv has accelerated recently, confounding farmers and veterinarians, who have ramped up their already stringent "biosecurity" measures since last spring. Those precautions include more aggressively disinfecting trucks and workers'' boots and clothing when they enter and leave farms and barns.
The United States Food and Drug Administration (FDA), the Department of Agricultureand pork-industry officials are examining a range of feed ingredients and manufacturing processes as well as other possible pathways for the virus, like contaminated air or dust particles carried from farm to farm.
Though the evidence is inconclusive, some researchers say that porcine plasma could be spreading the virus from adult pigs that show few symptoms, or that some plasma may have been contaminated in transit. The ingredient has been a mainstay of piglet diets in the US since the 1990s, after scientists discovered it provided antibodies to protect young pigsfrom disease and helped them switch from feeding from their mother to the grain-heavy diet common on livestock farms.
Last month, the Canadian Food Inspection Agency (CFIA) disclosed that it had found plasma contaminated with the virus, after multiple hog farms in Ontario that were hit by PEDv, and another farm on Prince Edward Island with a suspected case, all reported that they bought feed from the same vendor, Ontario-based Grand Valley Fortifiers.
The CFIA said that the virus was present in plasma that originated in the US and was obtained at the company that manufactured Grand Valley''s feed, which the agency has declined to identify. It said the plasma contained virus "capable of causing disease in pigs."
However, earlier this month the agency said laboratory tests in which it fed Grand Valley''s feed pellets to piglets failed to demonstrate that the feed, which contained plasma and many other ingredients, could cause infection. Still, Grand Valley recalled its products containing plasma and no longer uses the ingredient, said chief executive Ian Ross.
The USDA and the FDA, which have been investigating potential pathways for the virus''s spread, said they haven''t been able to link feed samples to a known case of the disease. The FDA has been studying the manufacturing process at the United Statesfacility that supplied plasma for the Grand Valley feed, and is seeking "to learn more" about the conditions the raw material is subjected to, said agency spokeswoman Siobhan DeLancey.
Scientists say studying animal feed is difficult because feed manufacturers mix and process their feed differently. Porcine plasma is one of more than 40 ingredients in typical piglet feed. "Many people think that feed is the most likely suspect, but practically speaking, we have no proof," said Greg Stevenson, a veterinary pathologist at Iowa State University who has studied the virus.
Suspicions already have roiled the half-dozen companies that manufacture plasma in the US and Canada; some farmers have stopped feeding the ingredient to their pigs, out of caution.
Sunterra Farms, of Acme, Alberta, recently stopped feeding plasma to the 300,000 pigs it raises each year in the United Statesand Canada.
Smithfield Foods, a unit of China''s WH Group Ltd. and the largest hog farmer and pork processor in the world, declined to comment on plasma. Maschoffs, North America''s largest family-owned pork producer, said that without firmer epidemiological evidence linking plasma to the virus it continues to use the ingredient in piglet diets while working with suppliers to ensure its safety.
The North American Spray Dried Blood and Plasma Protein Producers, which represents plasma makers, said porcine blood products that are properly sourced, collected and processed are safe and don''t contribute to the spread of the virus. Louis Russell, the group''s chairman, said that feed ingredients like plasma could be contaminated after processing, during transportation or mixing.
Porcine plasma is made from blood captured in chilled vats at slaughterhouses. It is treated with an anticoagulant and spun in a centrifuge to separate the plasma from blood cells, then transported in insulated trucks to processing plants. The plasma is shot through a spray nozzle into a heated chamber to evaporate excess water, leaving a powder that is run through stainless-steel dryers, bagged and shipped to feed companies.
Plasma makers say they collect blood only from healthy animals in federally inspected slaughter plants. But because the virus has only a mild effect on fully grown hogs, infected animals might not be identified at slaughter, said Liz Wagstrom, chief veterinarian for the National Pork Producers Council, a trade group.