Evaluation of combinations of nisin, lauric arginate, and ε-polylysine to control Listeria monocytogenes in queso fresco

Abstract

Listeria monocytogenes contamination is of great concern in queso fresco (QF), and listeriosis outbreaks linked to consumption of QF continue to happen. Hurdle approaches such as combining antimicrobials provide an alternative to improve QF safety. In this work, the efficacy of antimicrobial combinations of nisin (NIS), lauric arginate (LAE), and ε-polylysine (EPL) to inhibit L. monocytogenes growth in QF was evaluated. First, antimicrobials were screened for potential synergy in vitro. Later, antimicrobial treatments were challenged in QF inoculated with ~4 log 10 cfu/g of L. monocytogenes 5-strain cocktail and stored for 28 d at 4°C. Our results showed that combinations of NIS-LAE and EPL-LAE were synergistic in vitro. Limited antilisterial control was observed in QF treated with NIS, LAE, and NIS-LAE; however, EPL and EPL-LAE exhibited listeristatic effect in QF for up to 14 and 28 d of cold storage, respectively. Additionally, L. monocytogenes QF isolates had similar susceptibility to EPL or LAE. A consumer panel was able to distinguish between QF added with EPL (250 µg/g) + LAE (66.66 µg/g) and control QF, most likely associated with manufacturing and storage rather than antimicrobials' taste. Our results support the use of EPL-LAE combination to control L. monocytogenes growth in QF.

Fabrication of zein-modified starch nanoparticle complexes via microfluidic chip and encapsulation of nisin

“…L. monocytogenes counts in control cheeses reached approximately 5.5 Log CFU/g by day 14 of storage at 4 °C, an increase of about 2 Log CFU from the initial inoculum. Similar to our previous studies ( Feng et al, 2019 ; Ibarra-Sánchez et al, 2021 ; Ibarra-Sánchez et al, 2018 ; Martínez-Ramos et al, 2020 ), a discreet reduction in the pathogen counts was observed in cheeses added with free nisin compared to control cheeses. The limited antilisterial efficacy of nisin in Queso Fresco is the result of nisin's instability at near-neutral pH, and interactions with milk fat, caseins, and cations ( Ibarra-Sánchez et al, 2020 ).…”

Antimicrobial and Antibiofilm Effect of ε-Polylysine against Salmonella Enteritidis, Listeria monocytogenes, and Escherichia coli in Tryptic Soy Broth and Chicken Juice

“…The MIC of ε-PL in the co-cultured strain was 1.0 mg/mL. ε-PL has been shown to have antimicrobial effects against Gram-positive and Gram-negative bacteria, yeast, and fungi [ 31 , 32 , 33 ]. Some reports suggest that the optimal MIC levels are 0.1 and 0.05 mg/mL for S .…”

“…typhimurium , respectively [ 32 ]. In addition, L. monocytogenes and E. coli showed MIC values at 125 and 19.53 μg/mL, respectively [ 31 , 33 ]. These differences can be attributed to the use of the food grade (low purity) and the tested strain.…”

Recent Advances in Listeria Mitigation for Queso Fresco

“…32 EPL has also been shown to be listeriastatic when combined with LAE, over a 28 d shelf life, but consumers were able to differentiate the treated product. 33 Glycolipids, a biosurfactant, have been evaluated as a way of addressing L. monocytogenes contamination at different steps within the QF production. 34 This treatment was effective at reducing biofilms on polysterene and stainless steel.…”