Detection of Listeria Species in Fresh Produce Samples from Different Retail Shops in Canterbury, New Zealand.
At any of these steps a careless omission would give Listeria monocytogenes a chance to contaminate fresh vegetables, such as during storage conditions and/or sanitation conditions during packing processes and transport. At the end of 2014, a listeriosis outbreak related to caramel apples occurred, which led to 35 people being infected by L. monocytogenes.
Market D was a fruit and vegetable retail shop outlet where fresh produce was the major commodity sold. Four different types of vegetable samples were collected to evaluate the microbiological quality and the presence of Listeria spp. contamination during 6-weeks of sampling. Statistically significant differences were recorded for total plate counts using the Tukey
test. The microbial populations were highest in the cabbage and lettuce samples. The population of total microbes in carrots was slightly lower and significantly different from cabbage and lettuce. The APC in cucumber were lowest in the samples from Market D.
Twenty-five grams of a representative portion from each sample was introduced aseptically into a sterile stomacher bag containing 225 ml of peptone water. Listeria selective agar (CM0856,
OXOID) and DifcoTM plate count agar were plated the after making suitable dilutions.
The results of this study showed that cabbage and lettuce had similar levels of total microbial loads. However, the contamination of Listeria spp. in lettuce was higher than in cabbage. The total microbial load in carrot samples was higher in the cucumber samples while the prevalence of Listeria spp. was higher in the cucumber samples. Overall, all 4 different types of vegetable
samples had similar microbiological quality regardless of the market source.
Adv Food Technol Nutr Sci Open J. 2016; 2(3): 96-102. doi: 10.17140/AFTNSOJ-2-135