14B-3

D. B. MIN¹, M. S. Chung², and J. H. Lee². (1) The Ohio State University, Department of Food Science and Technology, 2121 Fyffe Road, Columbus, OH 43210, (2) The Ohio State University

Flavor is one of the most important qualities of beef to be acceptable to consumers. The objective is to study the effects of Pseudomonas putrifaciens and Acinobacter spp. on the flavor quality of aseptic ground beef by a combination of dynamic headspace analysis and sensory evaluation. Five grams of aseptically ground beef inoculated with Pseudomonas putrifaciens and Acinobacter spp. were transferred into a 30 ml glass serum bottle and sealed air tightly with Teflon rubber septa and aluminum cap. Sample bottles in quadruplicate were stored at 5°C under fluorescent light of 1000 lux for 0, 1, 2, 3, 4 and 8 days. The quality of samples were evaluated by a combination of sensory evaluation, measuring volatile compounds, and bacterial growth. The compounds were identified by mass spectrometry and gas chromatographic retention time comparisons. The correlation coefficient between Pseudomonas putrifaciens counts and volatile compounds formation was 0.92. Pseudomonas putrifaciens produced sulfur dioxide. Aseptic ground beef inoculated with Pseudomonas putrifaciens produced four times more dimethyldisulfide and dimethylsulfide than the aseptic ground beef after 8 days of storage at 5°C under light. Sensory data and Pseudomonas putrifaciens counts indicated that Pseudomonas putrifaciens were mainly responsible of the off flavor of beef during storage. Acinobacter spp. did not produce volatile compounds to affect the flavor quality of beef during storage. The contamination and growth of Pseudomonas putrifaciens during processing and storage of beef to maintain good beef flavor should be minimized.