Browsing by Subject "Modified atmosphere packaging"
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Item Multilayered membranes for modified atmosphere packaging(2013-05) Offord, Grant Thomas; Paul, Donald R.; Freeman, B. D. (Benny D.)This dissertation discusses, in brief, the production and transport property characterization of films made from the extrusion and biaxial stretching of [beta] nucleated isotactic polypropylene and the extrusion of PEBAX block copolymers. Multilayered films for modified atmosphere packaging applications were also produced by coextrusion and biaxial stretching of these two materials and similarly characterized. Current membranes for packaging applications are generally produced by coating a porous support with a polymeric solution to deposit an active layer for separation. The goal of this project is to displace membranes produced by solvent-based processes, which are environmentally hazardous and thus costly, with equivalent or superior materials produced using melt extrusion.Item Spoilage characteristics of ground beef with added lactic acid bacteria at abusive and refrigerated temperatures packaged in modified atmosphere and traditional packaging(2005-05) Hoyle, Amy R.; Brashears, Mindy M.; Brooks, Chance J.; Thompson, Leslie D.Lactic acid bacteria (LAB) can reduce Escherichia coli O157:H7 and Salmonella spp. in ground beef during storage. Two packaging studies evaluated if LAB masked changes typically associated with the spoilage of ground beef displayed under refrigerated (0°C) or abusive (10°C) temperatures. Packaging consisted of traditional (foam trays wrapped with permeable film) and MAP packaging (80% O2 and 20% CO2). To mimic industry practice, one-half of MAP samples contained 1000 ppm added rosemary oleoresin. Microbial and sensory analyses were conducted to determine spoilage endpoints. At 0°C, traditionally packaged LAB samples had significantly lower yeast and mold (YM) counts than controls throughout display. Among traditional packages, there were no significant differences in coliform, Brochothrix thermosphacta, and Pseudomonas spp. counts between LAB treatments. At abusive display temperatures, there were no significant differences in coliform, YM, B. thermosphacta, and Pseudomonas spp. counts between traditionally packaged LAB treatments. At 0°C and 10°C, total plate counts and LAB populations in both traditional and MAP packaged LAB inoculated samples were significantly higher than the control. In MAP packaging, no significant differences existed between LAB treatments for YM, coliform, B. thermosphacta, and Pseudomonas spp. No significant differences in trained or consumer sensory color and odor scores existed between LAB and controls for traditional and MAP packaging indicating spoilage was not masked. Therefore, LAB can be added to ground beef as an antimicrobial agent in traditional and MAP packaing. In addition, LAB may slow lipid oxidation in traditionally packaged ground beef.Item Spoilage characteristics of ground beef with added lactic acid bacteria at abusive and refrigerated temperatures packaged in modified atmosphere and traditional packaging(Texas Tech University, 2005-05) Hoyle, Amy R.; Brashears, Mindy M.; Brooks, Chance J.; Thompson, Leslie D.Lactic acid bacteria (LAB) can reduce Escherichia coli O157:H7 and Salmonella spp. in ground beef during storage. Two packaging studies evaluated if LAB masked changes typically associated with the spoilage of ground beef displayed under refrigerated (0°C) or abusive (10°C) temperatures. Packaging consisted of traditional (foam trays wrapped with permeable film) and MAP packaging (80% O2 and 20% CO2). To mimic industry practice, one-half of MAP samples contained 1000 ppm added rosemary oleoresin. Microbial and sensory analyses were conducted to determine spoilage endpoints. At 0°C, traditionally packaged LAB samples had significantly lower yeast and mold (YM) counts than controls throughout display. Among traditional packages, there were no significant differences in coliform, Brochothrix thermosphacta, and Pseudomonas spp. counts between LAB treatments. At abusive display temperatures, there were no significant differences in coliform, YM, B. thermosphacta, and Pseudomonas spp. counts between traditionally packaged LAB treatments. At 0°C and 10°C, total plate counts and LAB populations in both traditional and MAP packaged LAB inoculated samples were significantly higher than the control. In MAP packaging, no significant differences existed between LAB treatments for YM, coliform, B. thermosphacta, and Pseudomonas spp. No significant differences in trained or consumer sensory color and odor scores existed between LAB and controls for traditional and MAP packaging indicating spoilage was not masked. Therefore, LAB can be added to ground beef as an antimicrobial agent in traditional and MAP packaing. In addition, LAB may slow lipid oxidation in traditionally packaged ground beef.