Anti-listerial activity of active high-methoxyl pectin films incorporated with Latilactobacillus curvatus CRL705 bacteriocins: Effectiveness assessment in ham

Abstract

Listeria monocytogenes is a foodborne pathogen able to survive, proliferate at refrigeration temperatures and contaminate a wide variety of foods, particularly chilled meat and ready-to-eat (RTE) meat products. One of the major challenges for the food industry in preventing the proliferation of spoilage and pathogen microorganisms lies in food packaging innovation. In this study, edible films were developed to control Listeria monocytogenes in cooked ham. An active film with antimicrobial properties was formulated from high-methoxyl pectin (HMP) and lactocin AL705 (AL705), a bacteriocin produced by Latilactobacillus (Lat.) curvatus CRL705. The optical, mechanical, and antimicrobial properties of the edible films were measured to determine the effects of AL705 on the film matrix. The minimum inhibitory concentration (MIC) of the bacteriocin used for film activation was 1.25 mg/mL. The incorporation of AL705 into the films did not significantly affect (p ≥ 0.05) moisture content, color parameters (L*, a*, DE*), elongation at break, or tensile strength compared with control films (HMP/Control). However, HMP/AL705 films exhibited lower water vapor permeability (p ≤ 0.05) and reduced transparency. The incorporation of AL705 did not significantly alter peak intensity or generate new peaks in the FTIR spectra. SEM micrographs revealed surface modifications in films containing bacteriocin AL705 compared with the control films. In edible films activated with AL705 at 4 °C, the growth of L. monocytogenes was completely inhibited in cooked ham for 7 days. Although the Listeria load increased toward day 14, it remained satisfactorily controlled in samples treated with HMP/AL705 films compared with samples treated with HMP/Control films. A similar trend was observed at 10 °C, which was used as the abuse temperature. Therefore, HMP films incorporated with lactocin AL705 may represent a promising alternative for functional food packaging aimed at improving food preservation.