30C-34 |
Effect of exogenous ascorbyl palmitate and alpha-tocopherol on fresh beef packaged under modified atmospheres. II. Microbiological profile. |
C. R. A. SOUZA1, S. M. I. Saad, and M. N. Oliveira. (1) Depto. Tecnologia Bioquímico-Farmacêutica, Universidade de São Paulo, Av. Prof. Lineu Prestes, n.580, bl.16., São Paulo, 05508-900, Brazil Microbial flora development and meat color are important determinants of the quality of fresh beef. Shelf life can be prolonged considerably by packaging the beef in modified atmosphere (MAP) with high levels of O2, to prolong color stability; CO2, to inhibit microbial growth; and storage at low temperature. Besides, ascorbyl palmitate and alpha-tocopherol delay the oxymyoglobin and lipid oxidation. Our objective was to study the microbiological profile of fresh beef as affected by ascorbyl palmitate and alph-tocopherol dip treatment and MAP storage. Fresh beef steak samples were dipped into antioxidant solutions with 0.15 to 0.85% (p/v) of ascorbyl palmitate and 0.02 to 0.14% (p/v) of alpha-tocopherol, based on a central composite design (DCC). Afterwards, samples were packed under modified atmospheres: A (0% O2: 100% N2); B (20% O2: 80%N2); C (50% O2: 50% CO2); and D (80% O2: 20% CO2). Microbial counts were determined in the samples stored at 4ºC for 0, 3, 7 and 10 days. It was observed that high concentrations of alpha-tocopherol in the dip solution resulted in the inhibition of lactic acid bacteria, psychrotrophs and mesophiles growth in beef kept under all atmospheres tested. These concentrations are also adequate for the color and TBARS parameters. Higher levels of ascorbyl palmitate tended to inhibit psychrotrophs and mesophiles growth when atmosphere C was employed, and lactic acid bacteria growth when atmosphere A was employed. Yeast and molds, total coliforms and E. coli counts were similar throughout storage for all dip solutions and packaging conditions tested. Dip solution of ascorbyl palmitate plus alpha-tocopherol and MAP may be an additional hurdle to MAP and GMP in preventing growth of microorganisms during storage of beef, besides delaying the oxymyoglobin and lipid oxidation.
Session 30C, Muscle Foods: Tenderness, Quality, Processing, Marination, Oxidation, and Shelf-Life
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