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

• Main Authors: Lucilla Iacumin, Giorgia Cappellari, Andrea Colautti, Giuseppe Comi
• Format: Article
• Language: English
• Published: MDPI AG 2020-06-01
• Series: Microorganisms
• Subjects: cooked cubed ham; bioprotective; <i>Listeria monocytogenes</i>; bioprotection
• Online Access: https://www.mdpi.com/2076-2607/8/6/898

The aim of this work was to study the presence of <i>Listeria monocytogenes</i>, as well as the potential activity of two bioprotective cultures (Lyocarni BOX-74 and Lyocarni BOX-57), versus a mix of three <i>L. monocytogenes</i> strains that were intentionally inoculated in cooked cubed ham, packaged in Modified Atmosphere Packaging and stored at different temperatures. The bioprotective cultures limit <i>L. monocytogenes</i> 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 <i>L. monocytogenes</i> 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 a_w ≤ 0.92, or pH ≤ 5.0 and a_w ≤ 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 <i>L. monocytogenes</i> growth. Consequently, these products can easily fall into category 1.3 (ready-to-eat foods that are not favourable to <i>L. monocytogenes</i> growth, other than those for infants and for special medical purposes), in which a maximum concentration of <i>L. monocytogenes</i> of 100 CFU g⁻¹ is allowed.