Prevalence of Listeriaspecies in Fresh Salad Vegetables and Ready-to-Eat Foods Containing Fresh Produce Marketed in Canterbury, New Zealand

Abstract

Fresh produce, the most common food, is source of high value nutrients in human diet. However, some pathogenic bacteria associated with fresh produce may cause illness. For example, Listeria monocytogenes is a microorganism that causes a disease of variable severity, such as mild gastroenteritis, severe infections of the blood stream and/or the central nervous system, and even leads to abortion in pregnant women. The aim of this study was to determine the prevalence of Listeria spp. in fresh produce. Four common fresh vegetables (lettuce, car-rot, purple cabbage, green cabbage) were tested in the amount of Listeria spp. over a 5-week period, and eight individual samples of each fresh vegetable were collected from two fruit and vegetable markets each week. Listeria spp. were detected in all the purple cabbage samples collected from these two markets. Listeria spp. were also present in 60% and 100% of the green cabbage samples obtained from market 1 and market 2, respectively. Listeria spp. were found in the lettuce samples collected from both markets during week 1 to week 3. Carrot samples had the lowest percentage (20%) of Listeria spp. Generally Listeria spp. were present in all the four vegetables sampled. However, variations were recorded between vegetable types and sources. Selected ready-to-eat products containing fresh produce were also collected to test the presence of Listeria spp. and it turned out that two samples were Listeria spp. positive. Our data suggested that Listeria spp. were generally prevalent in fresh vegetables and Ready-to-Eat (RTE) food products containing fresh produce.