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Title: RAPID METHODS TO PREDICT BACTERIAL LOAD IN GROUND BEEF

Author
item VENKITANARAYANAN - UNIV OF CONN
item FAUSTMAN CAMERON - UNIV OF CONN
item Berry, Bradford

Submitted to: International Congress of Meat Science and Technology Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/21/1994
Publication Date: N/A
Citation: N/A

Interpretive Summary: Ground beef often has very limited shelf-life because of the variety of raw material sources and the mixing steps involved in processing. Traditional methods for determining bacterial numbers, being time- consuming, frequently provide answers on ground beef when the product is no longer acceptable in terms of sight and smell. This study evaluated four rapid tests as potential indicators of bacterial numbers in fresh and frozen ground beef. Resazurin reduction time and color absorbance of recovered bacteria proved to be slightly better indicators of bacterial numbers than fluorescein diacetate hydrolysis and aminopeptidase activity. Use of meat color changes was not as effective in predicting bacteria numbers. Meat color is often used by consumers as an indicator of meat freshness.

Technical Abstract: Fluorescein diacetate hydrolysis (FDA), resazurin reduction time (RR), aminopeptidase activity (AP), absorbance at 600 nm (A600), aerobic plate count (APC) and color ("a" value) of meat were monitored in refrigerated ground beef patties during storage. Analyses were also performed on spoiled, frozen patties to determine if freezing would alter the measured variable responses. Throughout the experiment, as bacterial load (APC) increased, FDA, AP, and A600 increased, while RR decreased. Regression analysis between APC and each of the other parameters revealed "r" square values of 0.88, 0.90, 0.86, 0.93, and 0.78, for FDA, RR, AP, A600 and "a" value, respectively.