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Evaluation of Mechanically Tenderized Beef and the Implications for Industry Changes


To determine the transmission of pathogens from the surface to deep muscle tissue in steaks after mechanical tenderization. To determine successfulness of the concept of blade tenderization methods. To development of potential ways to reduce microbial load when used in conjunction with mechanical tenderization.

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NON-TECHNICAL SUMMARY: Over the past few years there have been a multitude of beef recalls associated with contamination of beef with Escherichia coli O157:H7 as well as other harmful bacteria. Due to the millions of pounds of beef that has been recalled due to the possible contamination with these harmful bacteria, government legislation is working to strengthen programs which will reduce the likelihood of contamination of meat products. While it is most certainly a need to have strict food safety measures in place to protect consumers, there is also necessity to assess the potential risks that are associated with current processing technologies to alleviate any unnecessary preventive measures. This is not only true with large corporations who are key players in the meat industry but with small processors as well. With the increasing number of regulations applying to the meat industry, there is an increasing burden to small processors. Many small processors have a lack of knowledge, decreased productivity and increased cost associated with meat production as more regulations are implemented. This all adds up to a decrease in profitability and many processors are not going to be able to overcome the financial burden and will lose the ability to sustain their business. While there has been some research on this topic, it is not all inclusive and does not provide for specific recommendations that processors should consider when making decisions for the benefit of their company. Current research also does not provide a definitive reason to consider mechanical tenderization a food safety concern as long as current regulations are being followed. This project will look at factors associated with food safety and beef production that follow along with impending legislation to strengthen the safety of our meat supply. Specifically, the project will evaluate the need for measures that could or should be implemented for testing protocol of major pathogens such as Escherichia coli O157:H7 in non-intact beef products aside from ground products. Samples will be taken of surface and of deep muscle tissue after tenderization to determine if there are transfer patterns of bacteria into the inner tissue of beef. The long-term goal of this project is to help government as well as processors evaluate what regulations are needed as well as helping to identify intervention strategies in the processing plant to assure that the best possible effort is being applied when producing the safest meat supply. The overall objectives of this project are specifically to identify the transfer pattern of Escherichia coli species, including specifically Escherichia coli O157:H7 in non-intact beef products and to develop suggested guidelines for cleaning equipment in an effective manner to provide a hurdle for transmission of pathogens. There are also potential ingredients which could be applied to the surface of meat in conjunction with mechanically tenderizing as an antimicrobial. These products could not impart a flavor difference on the meat, and need to be researched. <P>APPROACH: Steaks cut to a thickness of 2.5 cm will be obtained from striploins. Surface slices will be taken randomly and from each steak to obtain a composite sample from each loin. The samples will then be plated to determine what floras are naturally present on the surface of striploins. After sampling the surface, the product will then be tenderized using the appropriate method and the deep muscle tissue sampled to identify the transmission of the natural flora from those steaks. The cores will then be sampled for the presence of the flora which were inside the deep tissue of the steak after tenderization. This procedure will also be applied to control steaks which are not tenderized. Next steaks will be inoculated with a specific organism such as E. coli K12, the non-pathogenic form of E. coli., and tenderized, followed by the tenderization of uninoculated steaks directly after the equipment has come in contact with the inoculated steak. The steaks will be placed under UV light to kill any surface bacteria that are within the natural flora of the steaks. Five of the steaks will then be inoculated with K12. The inoculated steak will be tenderized with the hand blade tenderizer followed by five additional steaks that were placed under UV light, but not inoculated. The deep muscle tissue of the inoculated steak as well as the subsequent ones would be sampled as described above to determine the presence of the specific organism. During this process, then equipment will be sampled to see if the needles retain any of the inoculant. Blades will be fully cleaned and sanitized between repetitions. The transfer of the target organism will be followed through the progression of uninoculated steaks through the blade tenderizer. If transfer of this particular organism is found, the more pathogenic strain of E. coli O157:H7 could be used as inoculants to provide a more definitive transfer pattern of specific organisms of concern to the meat industry. Another strain of E. coli which does not contain virulance factors that will be used is E. coli ECRC 97.0152. The necessity of using a tenderization method such as blade tenderization needs to be addressed. Striploins will be graded and cut in half. Eight 2.5 cm steaks will be removed from the center of striploins representing Select, Choice and Upper 2/3 Choice loins. Two steaks from each loin will be blade tenderized and two will remain intact. The steaks will be cooked according to AMSA (1995) guidelines to prepare for sensory evaluation and Warner-Bratzler shear force. For sensory panel, 2.5 cm cubes will be taken from the center of each steak to be served for sensory panel. A trained panel of at least six members will evaluate tenderness, juiciness and flavor for each sample. In addition to these components, there are antimicrobials that may reduce the presence of pathogenic bacteria on the surface of meat which will also be evaluated and tested in the same manner as above. Steaks will also have each ingredient applied on the surface and then will be cooked and presented to the trained sensory panel to determine any off-flavor imparted by each ingredient.

Bratcher, Christy
Auburn University
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