Growth and Expression of Virulence Genes of Listeria monocytogenes during the Processing of Dry-Cured Fermented “Salchichón” Manufactured with a Selected Lactilactobacillus sakei

Abstract

The effect of the dry-cured fermented processing of “salchichón” inoculated with a selected strain of Lactilactobacillus sakei (205) on the growth and transcriptional response of three virulence genes (plcA, hly, and iap) of Listeria monocytogenes was evaluated. For this, three different batches of “salchichón” were analyzed: batch B (inoculated only with L. sakei), batch L (inoculated only with L. monocytogenes), and batch L + B (inoculated with both microorganisms). Sausages were ripened for 90 days according to a traditional industrial process. The processing of “salchichón” provoked a reduction in L. monocytogenes counts of around 2 log CFU/g. The downregulation of the expression of the three genes was found at the end of ripening when the water activity (aw) of “salchichón” was <0.85 aw. The combined effect on the reduction in L. monocytogenes counts together with the downregulation in the expression of the virulence genes throughout the “salchichón” processing could be of great interest to control the hazard caused by the presence of this pathogenic bacterium.

Influence of plant protein‐dietary fiber composite gel and Lactiplantibacillus plantarum XC‐3 on quality characteristics of Chinese dry fermented sausage

“…The changes in the water content of sausages are shown in Figure 3c. During the drying and maturing period, the moisture content of the sausage decreased significantly faster ( p < 0.05), from about 60% to about 30%, which led to a decrease in the Aw inside the sausage and inhibited the growth of harmful microorganisms (Martin et al, 2021). The gel added increased the initial moisture content of sausages because of the moisture in the gel.…”

“…During the drying and maturing period, the moisture content of the sausage decreased significantly faster (p < 0.05), from about 60% to about 30%, which led to a decrease in the Aw inside the sausage and inhibited the growth of harmful microorganisms (Martin et al, 2021).…”

An Overview of Ripening Processes

“…The majority of these microorganisms, including some molds, yeasts, gram-positive catalase-positive cocci (GCC+), and lactic acid bacteria (LAB), exert a beneficial influence on the formation of the desired sensory attributes. State that the appearance of these beneficial bacteria is not exclusive to these goods, as they are usually exposed to the indigenous microbiota of the processing environment [38][39][40].…”

Biocontrol of Pathogen Microorganisms in Ripened Foods of Animal Origin

“…Once the inhibitory capacity of a BCA in a culture medium has been proven, it is necessary to evaluate it in the ripened foods of animal origin following their industrial processing. For this purpose, different studies have, firstly, inoculated the BCAs at the beginning of the product manufacturing and tested their antimicrobial activity [ 34 , 38 , 68 , 163 ] and, secondly, tested the BCA implantation at the end of the ripening [ 31 ]. Different molecular techniques are available to check whether the protective microorganisms have been correctly implanted in the product, such as analysis of chromosomal DNA via pulsed field gel electrophoresis (PFGE).…”

“…Moreover, consumers currently demand clean label products that are free from chemical additives and preservatives [ 29 ]. Therefore, preventive measures, such as strategies to control pathogenic or spoilage microorganism in ripened foods of animal origin, are currently based on the use of biocontrol agents (BCAs) of either microbial [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ] or plant-based origin, such as essential oils (EOs) and spices [ 40 , 41 , 42 , 43 , 44 , 45 ]. These treatments should have a low environmental impact and a neutral or positive influence on the sensory properties of the ripened foods of animal origin, since their organoleptic characteristics are well defined and highly appreciated by consumers.…”