Modeling the effect of temperature and relative humidity on the ethylene oxide fumigation of Salmonella and Enterococcus faecium in whole black peppercorn
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EmailThis research investigated the effect of temperature and relative humidity conditions during ethylene oxide fumigation for inactivation of Salmonella and Enterococcus faecium NRRL B-2354 on whole black peppercorns.
Abstract
This research investigated the effect of temperature and relative humidity (RH) conditions during ethylene oxide (EtO) fumigation for inactivation of Salmonella and Enterococcus faecium NRRL B-2354 on whole black peppercorns. Black peppercorn samples were inoculated with a five-strain Salmonella cocktail or E. faecium inoculum. EtO (735.3 mg/L) fumigation was conducted at different treatment temperatures (46, 53, and 60 °C) and different RH levels (30,40, and 50%) for the inactivation of inoculated black peppercorn samples with different exposure times (2–180 min). The temperature, RH, and exposure time exhibit significant linear effects on microbial inactivation. Bacterial inactivation during EtO fumigation was described by the Weibull model with the R2 > 0.70 and RMSE < 0.20 log CFU/g at all conditions. The concave upward trend of the Weibull model indicated a tailing effect. The inactivation data were also used to develop the response surface model as a function of temperature, RH, and exposure time to predict the reduction of Salmonella or E. faecium on whole black peppercorn during EtO fumigation. The developed models predicted log reductions with RMSE of 0.48 and 0.45 log CFU/g for Salmonella andE. faecium, respectively. Technical information for developing and validating EtO fumigation for whole black peppercorn could be estimated based on the developed model.
