A Risk Assessment of Listeria monocytogenes of Shredded Cabbage Supply Chain

• Main Authors: Liu, Jui-Han, 劉睿涵
• Other Authors: Hsiao, Hsin-I
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/6uvu64

碩士 === 國立臺灣海洋大學 === 食品安全與風險管理研究所 === 107 === Listeria monocytogenes is ubiquitously prevalent in natural environments. This microorganism can survive and grow in low-temperature. Although Listeriosis, an infection caused by Listeria monocytogenes, is rarely reported, but the mortality is high. Thus, assessing and quantifying the risk of getting Listeriosis from eating ready-to-eat vegetables is important. In this study, the risk of detecting Listeria monocytogenes in shredded cabbage in a case company was assessed and quantified. Firstly, literature review was performed to collect relevant data such as the prevalence and concentration of Listeria monocytogenes in fresh vegetables. Secondly, time-temperature conditions at each stages of cabbage chain were collected by using data logger. There were two different shipping routes of the products in this study: north area route and middle area route. Thirdly, FMEA (failure mode and effect analysis) was used to evaluate the risk by questionnaire method, whereas the potential failure mode was identified by calculating the risk priority number (RPN). The results show that (1) the population of Listeria monocytogenes in shredded cabbage at the end of storage in restaurant was estimated to be 2.97 log CFU/package in north area and 2.88 log CFU/package in middle area. Moreover, the risk of detecting listeria higher than 100cfu/g in a package of cabbage is 2.49 × 10-3 in north area and 2.91 × 10-3 in middle area. (2) According to the scenario analysis developed in this study, good source control (Alt#1) (low prevalence and initial contamination) could reduce risk from 2.49 × 10-3 to 2.39 × 10-5 in the north area route and from 2.91 × 10-3 to 3.2 × 10-4 in the middle area route. This study found that the ideal condition for decreasing the risk is the scenario (Alt#5), which combining Alt#1~4 (Alt#1, low prevalence and initial contamination; Alt#2, no cross contamination during the process; Alt#3, reduce more bacterial levels when washing; Alt#4, good temperature control in each steps of supply chain). This condition could reduce risk from 2.49 × 10-3 to 1.78 × 10-6 in the north area and from 2.91 × 10-3 to 1.29 × 10-5 in the middle area. (3) FMEA results show that warehouse poor management is the riskier part of the supply chain. This factor is not included in the exposure assessment model in the research. In conclusion, the prevalence and initial contamination are the important influencing factors to the cabbage product in this case company. Thus, we suggest the company to pay special attentions on the sources of supply chains and the management of warehouse in order to reduce the risk of bacterial contamination and foodborne illness.