This study examined the use of ratio-frequency (RF) or a combination of RF heating and nisin to reduce the bacterial oad of vacuum packed and retail packed beef to extend shelf life while maintaining the quality of the raw meat product. After treatment, we studied the growth of E. coli biotype 1, Carnobacterium sp. "845" and Pseudomonas D17, on beef cores stored for 7 days at 7 deg C in retail packaging and for 6 weeks stored at 2 deg C in vacuum packaging. No reduction in bacterial counts was achieved with the radio-frequency treatment without a significant impact on the quality and appearance of the meat. A reduction in bacterial counts was achieved with the nisin treatment alone or combined with a mild RF treatment. The future of dielectric heating in fresh meat preparation for bacterial reduction is not very promising, except perhaps as a source of supplemental heat to the more effective bactericidal nisin treatment.
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