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Tackling Salmonella in ground beef could be the U.S. meat industry's most challenging task yet, according to James Marsden, professor of animal science at Kansas State University. The main cause for concern is the fact that scientists had previously wrongly identified the source of Salmonella but have now traced it to the lymphatic system of cattle, making it very hard to prevent, Food Safety News reported.

Scientists previously assumed that measures taken to control E.coli worked for Salmonella too, but apparently this is not the case, Marsden wrote on industry blog Meating Places. It was believed that Salmonella followed the same pattern as E.coli and was transferred from the beef hide to the carcass and then into the meat. However, while E.coli contamination incidence rates have been steadily falling over the past few years, Salmonella cases did not drop, causing researchers to dig deeper and eventually discover that Salmonella was inside the cattle's body to begin with, he explained.

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According to Food Safety News, the implications of this finding are yet to be analyzed but Marsden believes that some procedures may have to be changed. If a sample reveals that beef is tested positive for E.coli, an immediate recall is ordered. However, if Salmonella is found a recall is not started until humans are infected. The reason for this is the fact that the U.S. Department of Agriculture does not consider Salmonella to be an adulterant.

Marsden said there has been a request sent to the Department, asking for Salmonella to be declared an adulterant, but the federal agency has not made its decision yet.