On Tuesday, April 24, 2012, the California Department of Food and Agriculture (CDFA) and the U.S. Food and Drug Administration (FDA) were informed by the CDFA Animal Health Safety Service (AHSS) Division that a brain sample collected from a dead cow at the Baker Commodities rendering transfer station in Hanford, California tested positive for L-type atypical bovine spongiform encephalopathy (BSE). While cases of classical BSE have been clearly linked to the use of contaminated meat and bone meal (MBM) as an ingredient in cattle feed, the origin of atypical strains of BSE is unknown. Given the scientific uncertainty about the origin of the L-type strain of BSE, FDA and CDFA conducted a feed investigation to try to determine if any feed supplied to the index premises since the birth of the index cow could have been manufactured with or cross-contaminated by ingredients that are prohibited for use in feed for ruminant animals.
FDA published BSE feed regulations in 1997 and 2008 to protect against cattle exposure to the BSE agent through animal feed. The 1997 “feed ban” (21 CFR 589.2000) prohibits feeding mammalian protein, with certain exceptions such as for milk products and blood products, to ruminants. The 2008 “enhanced feed rule” (21 CFR 589.2001) addresses concerns that the 1997 rule might not completely eliminate the potential for cattle to be exposed to infectivity as a result of cross-contamination during feed manufacturing or distribution, or as a result of on-farm misfeeding of swine feed, poultry feed, or pet food to cattle. To further reduce the BSE risks associated with cross-contamination and on-farm misfeeding, the 2008 rule banned the use of the highest risk cattle tissues - the brain and spinal cord from cattle 30 months of age and older - in all animal feed.
To investigate whether the BSE positive cow in California had access to feed ingredients containing bovine origin MBM, the CDFA and the FDA visited the index dairy farm where they evaluated the dairy farm’s compliance with BSE feed regulations, obtained the feeding history of the index cow since her birth in September 2001 to the present, and identified all feed suppliers to those premises where the cow had resided since birth. An inspection for compliance with 21 CFR 589.2000 and 589.2001 (a BSE inspection) was then conducted at each of the feed suppliers identified. In addition, inspection reports from all previous inspections at the identified feed firms were reviewed to determine each firm’s history of using prohibited material in feed manufacturing, as well as each firm’s history of compliance with FDA’s BSE feed regulations. Particular attention was focused on controls in place at each facility to prevent cross contamination.
Review of the BSE inspection histories found that compliance with BSE feed regulations was excellent. None of the facilities had used prohibited material in their feed manufacturing during the entire period of interest. All historical BSE inspections at the 12 feed suppliers were NAI (no action indicated) for all inspections conducted over the period of interest. One facility had minor violations (VAI, or voluntary action indicated) for medicated feed good manufacturing practices (GMP) deficiencies. Prior to the period of interest, one firm was OAI for an April 2000 inspection because the firm had inadequate cleanout procedures and failed to label product potentially containing prohibited material with the required caution statement “do not feed to cattle or other ruminants”. The next inspection of that facility, in May 2001 (6 months before the date of birth of the index cow), found that the facility no longer used prohibited material.
Although none of the facilities had used prohibited material in their feed manufacturing during the entire period of interest, one facility distributed prohibited material but did not use it to manufacture feeds. This facility maintained separation between its manufactured feed and products for distribution that contained prohibited material. Six facilities used only vegetable origin protein sources such as whole and rolled corn, soybean meal, canola meal, distillers dried grain, corn gluten, wheat, almond hulls, rolled barley, cottonseed, sunflower meal, and beet pulp. Five facilities used blood meal (one of the five used only porcine origin blood meal). Two used feather meal, two used fish meal, and one used porcine origin MBM. One facility processed and manufactured with poultry waste. Three facilities distributed pet food or sold it to retail customers. All three of these facilities kept the pet food in an area of the facility separated from feed manufacturing, with posted signs saying “do not feed to cattle or other ruminants.”
The reporting form used to conduct BSE inspections requires the investigator to verify that facilities that do not use prohibited material have safeguards in place to assure that the facility does not receive prohibited material. All 12 firms had procedures in place for obtaining written certification or other assurances from suppliers that products contained no prohibited material. Written procedures at each facility also required that plant personnel review labels of incoming product for prohibited ingredients. The inspection reports showed that each feed supplier also had appropriate procedures for ensuring that vehicles used to haul incoming or outgoing product had either not previously hauled product containing prohibited material, or had been properly cleaned.
This feed investigation found that no feed suppliers to the index premises processed with prohibited material during the period of interest, that all feed facilities obtained appropriate assurances from their suppliers that incoming ingredients did not contain prohibited material, and that vehicle inspections and/or driver certifications were used by all facilities to ensure that products were not transported in vehicles that had hauled product containing prohibited material in the previous load. Based on these findings, the feed investigation team did not identify any conditions where feed ingredients supplied to the index premises had been manufactured with prohibited material, or where feed suppliers to the index premises did not have adequate safeguards in place to prevent cross-contamination during feed manufacture, storage, or transportation.