Shelf life extension of mozzarella cheese contaminated with Penicillium spp. using the antifungal compound ɛ-polylysine

Molds are one of the most important spoilage organisms on cheese which can lead to economic loss as well as raising public health concerns due to the production of mycotoxins. This study investigates the use of ɛ-polylysine as natural antimicrobial to inhibit fungal growth. The minimal inhibitory concentrations and minimal fungicidal concentrations of ɛ-polylysine were determined against Penicillium roqueforti, Penicillium nordicum, and Penicillium solitum. Then, polylysine was tested as surface antimicrobial for the preservation of mozzarella slice cheese inoculated with these Penicillium spp. and stored in plastic trays during 25 days. The minimal inhibitory concentrations calculated for the three fungi tested were of 60 mg/l whereas the minimal fungicidal concentrations detected were of 125–10,000 mg/l. The shelf life observed for the control experiments was of 15 days, and just using the ɛ-polylysine at 0.00625, 0.0125, and 0.025% was evidenced a shelf life increment in comparison with the control of 1–3 days.