Determine the efficacy of vacuum steam pasteurization to inactivate Salmonella PT30, Escherichia coli 0157:H7, and Enterococcus faecium on low moisture foods.
There has been increasing demand for nutritious foods among consumers. Low moisture foods such as flaxseeds, sunflower seeds, quinoa, and sesame seeds have been studied a great deal for their nutritious value. However, such foods are minimally processed and are usually consumed raw and several outbreaks due to Salmonella, and E.coli O157:H7 have been attributed to them. Several studies have shown that these pathogens are more resistant to dry heat in low moisture foods, and processes such as chemical treatments and blanching may have negative effects on product quality and functionality. Vacuum steam pasteurization is a technology that injects saturated steam under vacuum to supply heat which can be controlled to achieve desired temperature. We wanted to determine the efficacy of this technology in inactivation of pathogens on low moisture foods. Flaxseeds and quinoa seeds were separately inoculated with bacterial lawns of Salmonella PT30, E. coli O157:H7, and E. faecium to obtain a homogenous distribution. The inoculated flaxseeds (25g) were pasteurized at 75[degrees]C, 85[degrees]C, 95[degrees]C and 105[degrees]C after 24 and 48 hours post inoculation. Three 25g samples were run at each condition, and the experiment was repeated three times totaling nine samples at each pasteurization parameter. Similar average log reductions of 5.5 [+ or -] 1.2, 5.7 [+ or -] 0.4, and 5.3 [+ or -] 0.5 was observed after pasteurization for 1 minute at 75[degrees]C for Salmonella, E. coli O157:H7, and E. faecium respectively (P>0.05) on flaxseeds. Steam vacuum pasteurization is an effective method for inactivation of these pathogens on flaxseed achieving a 5 log after just 1 minute at 75[degrees]C. Also, the result suggests that Enterocuss faecium may be used as a surrogate for Salmonella, and E. coli O157:H7 when evaluating vacuum steam pasteurization for flaxseeds.
Manoj Shah (1), Julie Sherwood (1), Kari Graber (2) and Teresa Bergholz (1)
(1) North Dakota State University, Fargo, ND, (2) Napasol North America, Fargo, ND
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|Title Annotation:||Graduate Communications IN THE A. RODGER DENISON COMPETITION|
|Author:||Shah, Manoj; Sherwood, Julie; Graber, Kari; Bergholz, Teresa|
|Publication:||Proceedings of the North Dakota Academy of Science|
|Date:||Apr 1, 2015|
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