Listeria monocytogenes Survey in Cubed Cooked Ham Packaged in Modified Atmosphere and Bioprotective Effect of Selected Lactic Acid Bacteria

Abstract

The aim of this work was to study the presence of Listeria monocytogenes, as well as the potential activity of two bioprotective cultures (Lyocarni BOX-74 and Lyocarni BOX-57), versus a mix of three L. monocytogenes strains that were intentionally inoculated in cooked cubed ham, packaged in Modified Atmosphere Packaging and stored at different temperatures. The bioprotective cultures limit L. monocytogenes growth in cubed cooked ham stored either at 4 °C for 60 days and at 4 °C for 20 days and at 8 °C for 40 days. The inhibition at 8 °C is particularly useful for industrial cooked meat products, considering there are often thermal abuse conditions (8 °C) in the supermarkets. Both the starters can eliminate L. monocytogenes risk and maintain the products safe, despite the thermal abuse conditions. In addition, both culture starters grew without producing perceptible sensory variations in the samples, as demonstrated by the panel of the untrained tasters. The bioprotective LAB produced neither off-odours and off-flavours, nor white/viscous patinas, slime, discoloration or browning. Therefore, according to the obtained data, and despite the fact that cooked cubed ham did not show pH ≤ 4.4 or aw ≤ 0.92, or pH ≤ 5.0 and aw ≤ 0.94, as cited in the EC Regulation 2073/2005. It can be scientifically stated that cubes of cooked ham with the addition of bioprotective starters cultures do not constitute a favourable substrate for L. monocytogenes growth. Consequently, these products can easily fall into category 1.3 (ready-to-eat foods that are not favourable to L. monocytogenes growth, other than those for infants and for special medical purposes), in which a maximum concentration of L. monocytogenes of 100 CFU g−1 is allowed.

Evaluation of Different Techniques, including Modified Atmosphere, under Vacuum Packaging, Washing, and Latilactobacillus sakei as a Bioprotective Agent, to Increase the Shelf-Life of Fresh Gutted Sea Bass (Dicentrarchus labrax) and Sea Bream (Sparus aurata) Stored at 6 ± 2 °C

“…The use of bioprotective methods is a new, modern, and promising method largely used in other food fields to obtain good results against spoilage and pathogenic microorganisms without changing the texture, flavour, or odour of the product [ 23 , 63 , 64 ]. Among LAB, Latilactobacillus sakei is frequently used in bioprotective technology [ 65 , 66 ]. In particular, LAK-23, a commercialized bioprotective starter culture based on L. sakei , was chosen to try to achieve our objective, considering that LAB originally isolated from certain food products are the best starter cultures for these same products, because they would be more competitive than LAB from other sources [ 23 , 67 ].…”

Growth Inhibitory and Selective Pressure Effects of Sodium Diacetate on the Spoilage Microbiota of Frankfurters Stored at 4 °C and 12 °C in Vacuum

“…sakei strains, may contain acetate-sensitive Carnobacterium spp. strains [ 57 ]. Based on this study, the in situ performance of these mixed protective cultures may be altered, reduced or even suppressed after a potential failure of their Carnobacterium fraction to grow in cooked meat products formulated with SDA.…”

“…Based on this study, the in situ performance of these mixed protective cultures may be altered, reduced or even suppressed after a potential failure of their Carnobacterium fraction to grow in cooked meat products formulated with SDA. Many studies have so far contributed to the development and application of effective cultures for meat biopreservation [ 3 , 32 , 57 , 58 , 59 ]. However, very few studies have considered comparing the in situ antilisterial activity of commercial protective LAB cultures in cooked meat products formulated with and without lactate/acetate blends [ 11 ], while no relevant studies have so far evaluated potential differential selective pressure effects of SDA or SL against the LAB strain constituents of commercial bioprotective mixed culture preparations in situ.…”

Analysis of the Bioprotective Potential of Different Lactic Acid Bacteria Against Listeria monocytogenes in Cold-Smoked Sea Bass, a New Product Packaged Under Vacuum and Stored at 6 ± 2°C

“…Consequently, their shelf life is limited to 9-12 days. In fact, within a short time, tissue enzymes and contaminating microbial populations adapt to refrigeration temperatures, producing metabolites typical of spoilage, which consist of basic volatile nitrogen (ammonia compounds), trimethylamine, amines, peroxides, and compounds derived from the degradation of lipids (malonaldehyde; Joffraud et al, 2001;Comi, 2016;Iacumin et al, 2017Iacumin et al, , 2020. Therefore, for trout, salmon and other fish, smoking is increasingly used to extend their shelf lives up to 45-60 days under refrigeration.…”

“…Many studies have been carried out about different RTE food categories that can be contaminated by L. monocytogenes. Recent studies have evaluated the ability of LAB to control L. monocytogenes in food products such as cheese, sliced cooked cured pork shoulder, diced ham, fresh-cut lettuce, processed seafood, and mayonnaise-based seafood salads, cold-smoked salmon, hot-smoked sea bream, and so on (Bredholt et al, 1999;Mataragas et al, 2002;Allende et al, 2007;Mejlholm and Dalgaard, 2014;Aymerich et al, 2019;Bolìvar et al, 2020;Iacumin et al, 2020;Morandi et al, 2020). In particular, it was observed in sausages, a 1.5-2.5-log reduction of L. monocytogenes by the presence of bacteriocin-producing strains belonging to P. acidilactici, L. sakei, L. plantarum, and L. curvatus species.…”