Edible Corn‐zein‐based Coating Incorporated with Nisin or Lemongrass Essential Oil Inhibits Listeria monocytogenes on Cultured Hybrid Striped Bass, Morone chrysops × Morone saxatilis, Fillets During Refrigerated and Frozen Storage

Abstract

Listeria monocytogenes presents a serious threat to consumer safety because it is resistant to various food storage techniques, including reduced or modified atmosphere packaging, refrigerated storage, and increased salt concentration. Edible coatings incorporated with natural antimicrobials have been suggested to control pathogenic and spoilage bacteria on a variety of meat products. In this study, edible zein‐based coatings incorporated with nisin and lemongrass essential oil (LGEO; 8%) were evaluated for antibacterial action against L. monocytogenes and spoilage organisms on fresh, cultured hybrid striped bass, Morone saxatilis × Morone chrysops, under two storage conditions (refrigerated or frozen) and two packaging types (polyvinyl chloride [PVC] and vacuum packing) over time. Corn‐zein‐based edible coatings were found to be an effective carrier for nisin and LGEO. Fillets coated with nisin showed the largest decrease in L. monocytogenes cell counts in both PVC and vacuum‐packaged samples in both refrigerated and frozen product, while fillets coated with LGEO showed intermediate inhibition of L. monocytogenes cell counts, with the strongest LGEO antibacterial effect being found in frozen product regardless of packaging. Both nisin and LGEO treatments were most effective in PVC‐packaged fillets compared to vacuum‐packaged fillets, but the difference in bacterial loads between packaging methods was minor. Bacterial loads on refrigerated product tended to increase slightly after 5‐d storage regardless of coating treatment or packaging, whereas bacterial loads on frozen product remained stable or decreased with time up to 60 d regardless of coating treatment or packaging. Data from the present study indicate that application of edible coatings incorporated with essential oils not only promotes food product safety but also may satisfy the preferences of consumers.

Listeria monocytogenes is inhibited on fillets of cold‐smoked sunshine bass, Morone chrysops × Morone saxatilis, with an edible corn zein‐based coating incorporated with lemongrass essential oil or nisin

“…A lateral strip and two cross‐sectional pieces weighing approximately 25 g were removed and weighed in a Labplas 7.5″ × 12″ 4‐mil stomaching bag (Labplas, Quebec, Canada). Inoculation methods were as described in Hager, Rawles, Xiong, Newman, and Webster (), and briefly, a 1:10 dilution was made with peptone buffer, and the sample was pulverized in a stomacher for 1 min. For inoculated samples treated with nisin or LG, three dilutions each, ranging from 10 1 –10 3 and 10 2 –10 4 , respectively, were converted into a phosphate buffer (pH 7.2).…”

Improvement of the microbiological quality of Argentinian Port Salut cheese by applying starch‐based films and coatings reinforced with rice bran and containing natural antimicrobials

“…Costa, Maciel, Teixeira, Vicente, and Cerqueira (2018) mentioned that the incorporation of antimicrobials (nisin, natamycin, essential oils, lysozyme) in the starch‐based coating matrix resulted in a reduction of the spoilage, when considering post‐process contamination on the coating, since edible coatings have the capacity to maintain high concentrations of the active substance into the matrix preventing its migration and extended the shelf‐life. Likewise, Hager, Rawles, Xiong, Newman, and Webster (2019) reported that nisin contained in an edible coating (90,000 IU/15 ml film solution) based on corn‐zein has proven to be an effective bacteriocin against L. monocytogenes inoculated on the surface of a covered fish fillets (counts greater than 7 log in the non‐antimicrobial systems vs. 1 log counts in the nisin system on the fifth day of storage). Küçük, Çelik, Mazi, and Türe (2020) evaluated alginate and zein films as a carrier of natamycin in order to limit/prevent the mold growth on the surface of kashar cheeses.…”

Biopolymer‐based antimicrobial coatings for aquatic food products: A review

“…A study by Hager, Rawles, Xiong, Newman, and Webster (2019)) formulated a corn‐zein‐based edible coating incorporated with lemongrass oil (8%) and nisin (6 g). The authors coated fresh hybrid striped bass ( Morone chrysops × Morone saxatilis ) to inhibit the growth of Listeria monocytogenes under frozen and refrigerated storage.…”