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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Hydrodynamic Pressure Treatment on Inactivation of Escherichia Coli O157:h7 in Blade Tenderized Beef Steaks

Authors
item Patel, Jitu
item Williams Campbell, Anisha
item Liu, Martha
item Solomon, Morse

Submitted to: Journal of Muscle Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 10, 2004
Publication Date: October 5, 2005
Citation: Patel, J.R., Williams Campbell, A.M., Liu, M., Solomon, M.B. 2005. Effect of hydrodynamic pressure treatment on inactivation of Escherichia coli O157:H7 in blade tenderized beef steaks. Journal of Muscle Foods. 16:342-353.

Interpretive Summary: Blade tenderization (BT) of beef muscle is a treatment in which intact beef muscle is pierced with several tiny blades. The treatment is commonly used to make beef more tender and more palatable. During the treatment, it is possible that some of the surface bacteria could transfer to the interior of the beef muscle. Escherichia coli O157:H7 is one of the most important foodborne pathogens responsible for diseases associated with consumption of beef and beef products. Survival of internally transferred pathogens following cooking would be a potential threat to human consumption. Meat could also be tenderized using the emerging hydrodynamic pressure (HDP) treatment. Beef muscles were surface inoculated with five strains mixture of pathogenic bacteria E. coli O157:H7, and treated with BT, HDP, or BT followed by HDP (BTH). Treated beef muscles were cut into 1" beef steaks and grilled to 54.4ºC (undercooked), 62.8ºC (medium rare), and 71.1ºC (medium). Cooked beef steaks were analyzed for survival of pathogen using microbiology procedures. Pathogen survival after cooking was always higher in BT treated steaks than those of untreated steaks. This may be due to the migration of surface pathogen to the interior of the muscle by BT treatment, thereby protecting the pathogen from the lethality of heat. Pathogen populations in BTH treated steaks cooked to 71.1ºC were non-detectable and were significantly different from those BT treated steaks cooked to 71.1ºC. Results suggest that blade tenderization of intact beef muscle does transfer surface bacteria to the interior of the muscle, which would require either cooking to temperatures above 71.1 C or a treatment like HDP for inactivation of the pathogen.

Technical Abstract: Blade tenderization (BT) of beef muscle is a very common treatment utilized by the beef industry to increase beef tenderness, the most appealing eating quality of the beef. A study reported transfer of surface inoculated bacteria into the interior of the intact beef muscle during BT treatment. Escherichia coli O157:H7 is one of the most important foodborne pathogens responsible for several outbreaks associated with consumption of beef and beef products. Survival of internally transferred pathogens following cooking could be potential threat to human consumption. Beef strip loin was randomly assigned to four treatments: (1) control, (2) BT, (3) hydrodynamic pressure processing (HDP), and (4) BT followed by HDP (referred at BTH). Beef strip loin was surface inoculated with a cocktail containing five strains of pathogen and treated with above treatments. Control and treated beef steaks (2.5 cm) were cooked to 54.4ºC (undercooked), 62.8ºC (medium rare), and 71.1ºC (medium) on open-hearth Farberware grills. Surviving populations of inoculated pathogen were enumerated after treatment and cooking. HDP treatment reduced pathogen populations by 0.3 log10 CFU/g, which was not significantly different from untreated controls. At each endpoint cooking temperature, pathogen survival was always higher in BT treated steaks than those of untreated steaks cooked to corresponding temperatures. This could be due to the migration of surface bacteria to the interior of the muscle thereby protecting bacteria from the lethality of heat. Pathogen populations in BTH treated steaks cooked to 71.1ºC were non-detectable and were significantly different from those BT treated steaks cooked to 71.1ºC. Results suggest that blade tenderization of intact beef muscle does transfer surface bacteria to the interior of the muscle, which would necessitate elevated cooking temperatures (>71.1 C) or a treatment like HDP for inactivation of bacteria.

Last Modified: 10/22/2014
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