Elimination of Escherichia coli O157:H7, Generic Escherichia coli, and Salmonella spp. On Beef Trimmings Prior to Grinding Using a Controlled Phase Carbon Dioxide (CPCO2) System

Conclusions
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Studies showed 1500 psi CPCO2 for 15 min achieved the highest lethality (P<0.05) in challenged beef trimmings (TR) and ground beef (GR). Total Plate Count (TPC), Generic E. coli (GEC), E. coli O157:H7 (O157), and Salmonella spp. (SS) reached 0.83, 0.96, 1.00, and 1.06 log reductions, respectively. Bacterial reductions in ground beef (GR) were similar to beef trimmings (TR) (P≥0.05). After 5 days of simulated retail display, CIE L* and a*, reflectance (630/580nm) ratios were similar for all treatments (P≥0.05). CIE b* scores after 5 days of display were most acceptable at 1500 CPCO2 (b*, P≥0.05), regardless of the packaging conditions. In cooked patties, CIE L* values were similar (P≥0.05) when comparing packaging conditions within the treatments. After 5 days of refrigerated display, CIE L* values were slightly higher for patties packaged under 100% flushed CO2 (CO2) when compared to aerobic trays (AT). CIE a* and b* values and reflectance ratios exhibited very similar trends, both scores were similar (a*,b*, 630/580, P≥0.05) after simulated retail display for all the treatments. The extent of lipid oxidation, after 5 days of simulated retail display, scored higher in AT than CO2, with the highest values reached at 1500 psi CPCO2 (P<0.05). TBAR values in CO2 patties were able to maintain similar values to the control all throughout refrigerated storage (P≥0.05). Ground beef patties manufactured from treated beef trimmings scored higher values for tenderness (P< 0.05) when compared to non-treated. 750 psi CPCO2 appeared to have worse scores for juiciness, beef flavor intensity or off flavor intensity (P<0.05) than the 1500 psi CPCO2 treatment or the control.
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Deliverable
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The use of controlled phase carbon dioxide was able to reduce bacterial growth in ground beef patties while maintaining organoleptic properties.