The U.S. Food and Drug Administration reopened the comment period for its rule on what cow parts may be used in human products Monday because research completed since the interim rule was published has revealed traces of bovine spongiform encephalopathy (BSE) in parts of the intestine currently allowed in human food and drugs. In 2005, FDA issued its interim final rule, “Use of Materials Derived From Cattle in Human Food and Cosmetics,” which stated that a cow’s small intestine was safe for use in human products as long as the portion called the distal ileum had been removed. At the time, the distal ileum was known to be a potential reservoir for BSE, also known as mad cow disease, but other parts of the small intestine were considered safe. Since that time, studies have found low levels of BSE in other parts of the cow’s intestine, including the proximal ileum, jejunum, ileocecal junction, and colon, prompting concerns that perhaps the U.S. Department of Agriculture (which regulates meat safety) and FDA should also prohibit these parts from use in human foods and cosmetics. “The infectivity levels reported in these studies were much lower than the infectivity levels that were previously demonstrated in the distal ileum,” notes FDA. In light of these findings, FDA has reopened the comment period on its 2005 interim final rule in order to hear from anyone who has information on the topic. In its announcement of the reopened comment period, FDA says it believes that the trace levels of infectivity found in these other parts of the intestine don’t pose a risk of human exposure to BSE in the United States. Now, “We want to hear from other people,” says Sebastian Cianci, spokesperson for FDA. “From what we’re seeing, we’ve concluded that there wouldn’t be a measurable reduction of risk from removing other parts. However, we want other people to weigh in before a final determination is made.” In reaching its conclusion, FDA says it also considered a recent opinion from the European Union Food Safety Authority on the risk of BSE from parts of the small intestine other than the distal ileum. A look at the opinion handed down from EFSA’s Panel on Biological Hazards shows that the group was unable to draw a conclusion about the safety of other parts of a cow’s intestine. “Due to limitations in the data currently available, an accurate quantification of the amount of infectivity in the intestinal parts other than ileum of Classical BSE infected cattle at different stages of the incubation period cannot be provided,” says the panel in its conclusion. The reopened comment period has been posted in the Federal Register and is available here. Comments can be submitted by clicking the “Submit a Formal Comment” button in the upper right hand corner of the page.