• Journal of Food Hygiene and Safety
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• v.27 no.2
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• pp.117-126
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• 2012

This study was conducted to assess the levels of microbiological hazards of preprocessed Namuls, which were served at the school foodservice. 19 preprocessed ground or root vegetables were collected from 21 schools in May to June of 2011. Heavy contamination of aerobic plate counts (from 3.39 to 8.42 logCFU/g) and total coliform groups (from 3.16 to 7.84 logCFU/g), enterobacteriaceaes (from 2.53 to 7.55 logCFU/g) were detected in preprocessed Namuls. In addition, the detection rates of Escherichia coli, Staphylococcus aureus and Bacillus cereus (emetic form) were 4.3%, 11.7% and 2.1%, respectively. In addition, sanitary indicative bacterium at preprocessing steps of root vegetables (lotus root, burdock root, bellflower root) and blanched Namuls (bracken, sweet potato vine, chinamul) were analyzed. Aerobic plate counts, coliform groups, and enterobacteriaceaes were not effectively removed during preprocessing including washing and soaking steps. In the case of blanched Namuls (bracken, sweet potato vine, chinamul), contamination levels increased more after drying process and no significant reduction effect on the levels of microbial contamination was observed during preprocessing steps. Thus, effect of preprocessing steps on the microbiological hazards in Namuls must be reevaluated to improve the microbiological quality of preprocessed Namuls at the school foodservice and retail markets.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1690-1700
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• 2013

The objective of this study is to develop and validate predictive growth models for Bacillus cereus (diarrhea type) vegetative cells, spores and Staphylococcus aureus in preprocessed Namul (bracken and Chwinamul) and root vegetables (bellflower and burdock). For validation of model performance, growth data for S. aureus in preprocessed vegetables were collected at independent temperatures (18 and $30^{\circ}C$) not used in the model development. In addition, model performance of B. cereus (diarrhea type) in preprocessed vegetables was validated with an emetic type of B. cereus strain. In primary models, the specific growth rate (SGR) of the B. cereus spores was faster than that of the B. cereus vegetative cells, regardless of the kinds of vegetables at 24 and $35^{\circ}C$, while lag time (LT) of the B. cereus spores was longer than that of the B. cereus vegetative cells, except for burdock. The growth of B. cereus and S. aureus was not observed in bracken at temperatures lower than 13 and $8^{\circ}C$, respectively. The LT models for B. cereus (diarrhea type) in this study were suitable in predicting the growth of B. cereus (emetic type) on burdock and Chwinamul. On the other hand, SGR models for B. cereus (diarrhea type) were suitable for predicting the growth of B. cereus (emetic type) on all preprocessed vegetables. The developed models can be used to predict the risk of B. cereus and S. aureus in preprocessed Namul and root vegetables at the retail markets.