Inactivation of Listeria monocytogenes in Raw Fruits by Enterocin AS-48

Abstract

The purpose of this study was to determine the effect of enterocin AS-48 on Listeria monocytogenes CECT 4032 in fruits and fruit juice. Fruits were contaminated with a L. monocytogenes cell suspension, washed with enterocin AS-48 (25 microg/ml) or with sterile distilled water as control, and stored at different temperatures (-20, 6, 15, 22 degrees C). Washing treatments significantly inhibited or completely inactivated L. monocytogenes in strawberries, raspberries, and blackberries stored at 15 and 22 degrees C for up to 2 days and in blackberries and strawberries at 6 degrees C for up to 7 days. Washing treatments with enterocin AS-48 also reduced viable counts in sliced melon, watermelon, pear, and kiwi but did not avoid proliferation of survivors during storage at 15 and 22 degrees C. Added enterocin (25 microg/ml) completely inactivated L. monocytogenes in watermelon juice within 24 h. To enhance the antilisterial activity of treatments, enterocin AS-48 was tested in combination with other antimicrobial substances on sliced melon stored at 22 degrees C. The combinations of enterocin AS-48 and trisodium trimetaphosphate, sodium lactate, lactic acid, polyphosphoric acid, carvacrol, hydrocinnamic acid, p-hydroxybenzoic acid, n-propyl p-hydroxybenzoate, or 2-nitropropanol showed increased antilisterial activities compared with each antimicrobial tested separately. Washing treatments with enterocin AS-48 in combination with 12 mM carvacrol, as well as with 100 mM n-propyl p-hydroxybenzoate, avoided regrowth of Listeria during storage at 22 degrees C. Results from this study indicate that enterocin AS-48 alone or in combination with other preservatives could serve as an additional hurdle against L. monocytogenes in fruits and fruit juices.

Effect of combined physico-chemical treatments based on enterocin AS-48 on the control of Listeria monocytogenes and Staphylococcus aureus in a model cooked ham

“…Further experiments carried out in fruits and fruit juices have shown that the anti-listeria effect of AS-48 (25 lg ml À1 ) depended on the fruit type and was much more effective in juices, probably due to the more homogeneous distribution of the enterocin in the liquid food matrix. In this case AS-48 showed also to be in general more effective at low temperatures (6-20°C) (Cobo Molinos et al, 2008).…”

Fate of Listeria monocytogenes in Fresh Apples and Caramel Apples

“…Although the listeriosis outbreak evaluated here is the first to be attributed to whole caramel apples, studies have shown that L. monocytogenes is capable of both surviving and growing on raw fruits such as whole and cut melons (13,14,20,23,27), melon pulp (26), cut pears (1,11,23), and whole and cut berries (1,23). This pathogen also can proliferate on fresh-cut apple slices when contamination occurs after processing procedures, such as peeling and cutting (2, 4, 12).…”

Inactivation of Listeria in Foods Packed in Films Activated with Enterocin AS-48 plus Thymol Singly or in Combination with High-Hydrostatic Pressure Treatment

“…Previous studies have shown that L. monocytogenes can grow in a number of vegetables [32][33][34], in non-acidic fruits [35,36] and in acidic fruits such as tomatoes [37], peeled Hamlin oranges [38], sliced raspberries, pear or kiwi [36], and in Golden Delicious apple slices [39,40]. In 2014, a listeriosis outbreak occurring in the USA was linked to commercially-produced, prepackaged whole caramel apples [4].…”