Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 3, 2006
Publication Date: June 24, 2006
Citation: Hwang, C., Tamplin, M.L. 2006. The effect of sodium lactate and sodium diacetate on the behavior of listeria monocytogenes in ham stored at various temperatures. Abstract. 052-01. Technical Abstract: Refrigerated ready-to-eat (RTE) meats contaminated with L. monocytogenes have been implicated in several listeriosis outbreaks. Lactate and diacetate have been shown to control L. monocytogenes in RTE meats at refrigerated temperature. However, there are no models describing their effects under temperature-abused conditions. Our objective was to model the behavior of L. monocytogenes in ham containing regulatory-permitted levels of sodium lactate (1.0-4.2%) and sodium diacetate (0.05-0.2%) at storage temperatures of 0 deg.- 45 deg. C. A 6-strain mixture of L. monocytogenes was inoculated into ground ham containing lactate and diacetate, and stored at various temperatures. A total of 19 combinations of these factors were selected by a central composite design. Mathematical equations describing the lag phase duration (LPD, h) and growth rate (GR, log cfu/h) of L. monocytogenes as a function of lactate, diacetate, and temperature were developed from the growth kinetic data. The LPD and GR equations were significant (p<0.001) with a regression coefficient of 0.96 and 0.74, respectively. Plots of response surface showed that L. monocytogenes had the shortest LPD at 25 deg. - 35 deg. C, and the highest GR at 12 deg. - 45 deg. C, depending on the concentrations of lactate and diacetate. Increases in levels of diacetate or lowering the storage temperatures extended the LPD. Increases in levels of lactate extended LPD only at lower diacetate concentrations. The GR was reduced as the storage temperatures decreased. Increases in levels of lactate or diacetate significantly reduced the GR at temperatures >27 deg. C. Below that temperature, selected concentrations of both additives were needed to achieve a lower GR. The resulting models may be used to estimate the behavior of L. monocytogenes in ham products containing lactate and diacetate stored at various temperatures. This information assists in determining concentrations of lactate and diacetate in ham to control the growth of L. monocytogenes at product temperatures likely encountered during manufacturing, distribution and storage.