Effect of Relative Humidity and Storage Temperature on the Behavior of Listeria monocytogenes on Fresh Vegetables. Issue 4 (31st October 2013)

• Record Type: Journal Article
• Authors: Likotrafiti, Eleni; Smirniotis, Petros; Nastou, Aikaterini; Rhoades, Jonathan
• Is Part Of: Journal of food safety. Volume 33:Issue 4(2013:Oct.)
• Page Start: 545
• Page End: 551
• Publication Date: 2013-10-31
• Subjects: Food adulteration and inspection -- Periodicals; Food contamination -- Periodicals; Food -- Analysis -- Periodicals; Food -- Microbiology -- Periodicals; Pathogenic bacteria -- Periodicals; Food handling -- Periodicals; Food preservatives -- Periodicals; 664
• DOI: 10.1111/jfs.12087
• Languages: English
• ISSNs: 0149-6085

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <sec id="jfs12087-sec-0001" sec-type="section"> <p>The survival and growth of <italic>L</italic><italic>isteria monocytogenes</italic> on fresh lettuce (<italic>L</italic><italic>actuca sativa</italic>), cucumber (<italic>C</italic><italic>ucumis sativus</italic>) epidermis and parsley (<italic>P</italic><italic>etroselinum sativum</italic>) under different relative humidity (RH) conditions and storage temperatures was studied. Inoculated vegetable pieces were stored at 10C for 7 days, 20C for 5 days, and 30C for 24 h, and at 53 and 90% RH. <italic>L</italic><italic>. monocytogenes</italic> was enumerated periodically by plate count. <italic>L</italic><italic>. monocytogenes</italic> did not grow on lettuce or parsley, but either declined in number or remained approximately constant. At cooler temperatures, a negative effect of low humidity on survival was observed. <italic>L</italic><italic>. monocytogenes</italic> grew on cucumber epidermis at all three temperatures, increasing from around 4.0 to around 5.5 log cfu/cm<sup>2</sup> when stored at 90% RH. Low RH negatively affected growth, limiting the increase to around 0.5 log cfu/cm<sup>2</sup> in most cases.</p> </sec> <sec id="jfs12087-sec-0002" sec-type="section"> <title>Practical Applications</title> <p>Fresh vegetables are increasingly important vehicles of foodborne pathogens. The majority of published studies on growth and survival of <italic>L</italic><italic>isteria monocytogenes</italic> on vegetables have been conducted on lettuce leaves and few data are available on the influence of relative humidity (RH). Growth of <italic>L</italic><italic>. monocytogenes</italic> may increase the risk to the consumer of some types of fresh vegetables. Maintaining lower RH during storage can decrease this risk, but may conflict with other product quality requirements. <italic>L</italic><italic>. monocytogenes</italic> does not grow on undamaged leaf surfaces under the conditions tested: when reviewing the literature it is important to differentiate between whole and shredded/cut leaves.</p> </sec> </abstract>