VACCINES FOR MEAT ANIMALS-AWAITING COMMERCIALIZATION

Meat industry is notorious for its vulnerability to dangers from deadly pathogens like Salmonella, virulent E.coli and others. Even if the sanitation regime that is required to keep the carcass free from microbial contamination is scrupulously deployed, the chances of cross contamination is still possible. If at all any sector of food processing faces high risk during its operations, it is the meat industry. Repeated pleas to allow low doses of gamma irradiation for maintaining freedom from pathogens have not yet been heard sympathetically and the risk factor remains as high as ever even to day. Against such a bleak background comes the news about development of vaccines that can be used for protecting animals till slaughter from the dangerous vectors. It is an interesting development that must please the industry to no end. Here is the take on this issue.

"Imperfect" but potentially effective technologies to control foodborne pathogens in beef pre-harvest are now available to government and industry, according to experts at a Nov. 9 meeting on pre-harvest pathogen control convened by the FSIS, the Animal Plant and Health Inspection Service, and the Agricultural Research Service. But can they be usefully implemented? A number of vaccine technologies have demonstrated a significant impact in reducing levels of E. coli 0157 and Salmonella bacteria detected in bovine feces pre-harvest, said Guy Loneragan, PhD, professor of food safety and public health at Texas Tech University in Lubbock, who presented the opening address at the meeting. For example, Epitopix/Pfizer Animal Health's SRP vaccine has shown a 40% to 60% reduction in Salmonella levels in feces in various commercial studies—and even more in so-called "high shedders." "These technologies have repeatable and predictable, if imperfect, efficacy. Even given that imperfect efficacy, if we have broad adoption of these technologies, we can have quite a meaningful public health impact. But how can we develop an environment that fosters their adoption?" The burden cannot be placed solely on producers, Dr. Loneragan said. "We have to find ways to pull these technologies through the system, not just at the packing plant level but at the retail level as well. Retailers need to develop a coordinated plan with packers, suppliers, and producers to share the costs and rewards of these technologies." At the meeting, industry representatives and other experts also suggested that more open testing of the vaccines in the marketplace is needed—and called for the FDA and USDA to expand licensure. "Right now, we have one vaccine that's conditionally licensed," said Dr. Loneragan. "But the conditional license comes with real barriers to adoption, such as a 60-day slaughter withdrawal. If there were a full license for these vaccines, sponsors could do studies that could show support for a shorter withdrawal period, which is much more practical. There has to be a mechanism by which the vaccines can move forward to full licensing and the industry can look at them in a more open and complete way."

One of the drawbacks cited against the vaccines is that they are not 100% effective, the degree of protection being in the range of 40-60%
which raises doubts about their overall impact under field conditions. Besides the conditional approval given to them stipulates that animals cannot be slaughtered for at least 60 days which naturally can put some burden to the industry in maintaining large stocks for long periods. If this work is carried forward there is good possibility that a multi-valent vaccine may emerge eventually that can take care of most predominant pathogens which are causing sleepless nights to the meat industry. In stead of leaving every thing to the industry to near the burden, Government agencies must play an effective supporting role in expediting such developments which will have far reaching benefits to the consumers.

V.H.POTTY
http://vhpotty.blogspot.com/
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