Growth potential of Listeria monocytogenes in six different RTE fruit products: impact of food matrix, storage temperature and shelf life

We tested the growth potential of Listeria monocytogenes on six RTE fruit products at low (4°C at the factory followed by 8°C retail/home storage) and abusive (4°C followed by 12°C) storage temperatures. Sliced coconut and fresh cut cantaloupe, as well as a fruit mix containing diced pineapple, cantaloupe, apples and grapes supported the growth of L. monocytogenes with a growth potential δ>0.5 log CFU/g over six days. Mangoes, a mix of diced kiwi, cantaloupe and pineapple as well as a mix of diced pineapple, mango, grapefruit, kiwi and pomegranate did not support a growth potential that exceeded 0.5 log CFU/g over six days. The growth potential of L. monocytogenes correlated significantly with the pH; no product with a pH below 4 showed a significant growth potential of L. monocytogenes. Time after inoculation was also a significant predictor of the growth potential, while the fruit type and storage temperature were not.