91E-28 |
Synergistic effect of Ozone and Microgard® for controlling Listeria monocytogenes in cured ham |
R. JHALA1, K. Muthukumarappan, J. L. Julson, and R. I. Dave. (1) Agricultural and Biosystems Engineering, south dakota state university, AE - 0218#2120, Brookings, SD 57007 Foods of muscle origin exposed to microbial contamination are responsible to cause microbial spoilage and food borne illness. Ozone is approved in USA as generally recognized as safe (GRAS) for food applications. Microgard® has been used as preservative in cottage cheese to inhibit psychrotrophic spoilage bacteria. There is a demand for safe and judicious usage of sanitizers, bleaching agents, preservatives and chemicals in food processing. We hypothesize that application of ozone and Microgard® hurdle concept can better control pathogens like Listeria monocytogenes in cured ham. Our objective was to evaluate the synergistic effect of ozone and Microgard® in controlling Listeria monocytogenes in cured ham. Effectiveness of ozone and Microgard® on survival of known number of Listeria monocytogenes in ham sample was investigated in a closed system. The survival rate of Listeria monocytogenes was studied as a function of gaseous ozone concentration (0.2, 0.5 & 1.0 ppm), Microgard® (1.0, 2.0 & 3.0%), temperature (10, 15 & 20 ºC), storage period (0, 5, 10 days) for a fixed treatment period of 30 min and storage temperature of 4 ºC. Our preliminary results indicate that there is a reduction (about 99.0%) in bacterial population, with only ozone treatment of 1.0 ppm. Microgard® alone has limited effect in controlling Listeria monocytogenes in cured ham. Microgard® in combination with ozone is less effective than only ozone treatment. As the storage period increases the microbial population increases at a reduced rate in ozone treated sample, while samples treated with Microgard® showed an increased rate. It would be interesting to see the effect of ozone and Microgard® on the cell structure of Listeria monocytogenes. This study may help to provide safe, organoleptically acceptable ready to eat meat products. Also, consumers may perceive ozone as a more “natural” treatment as compared to other conventional food processing treatments.
Session 91E, Nonthermal Processing: Nonthermal processing of foods
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