Control of Listeria monocytogenes in chicken dry-fermented sausages with bioprotective starter culture and high-pressure processing

Abstract

Listeria monocytogenes is one of the most relevant pathogens for ready-to-eat food, being a challenge for the food industry to comply with microbiological criteria. The aim of the work was to assess the behavior of L. monocytogenes in two types of chicken-based dry-fermented sausages during the fermentation and ripening, with or without a bioprotective starter culture (Latilactobacillus sakei CTC494). To complement the challenge testing approach, simulations with different predictive models were performed to better understand the role of contributing factors. The impact of post-processing strategies, such as high-pressure processing and/or corrective storage was assessed. The chicken meat was inoculated with a cocktail of three L. monocytogenes strains, mixed with other ingredients/additives and stuffed into small (snack-type) or medium (fuet-type) casings. Snack-type was fermented (22°C/3 days) and ripened (14°C/7 days), while fuet-type was ripened (13°C/16 days). At the end of ripening, HPP (600 MPa/5 min) and/or corrective storage (4 or 15°C/7 days) were applied. The suitability of HPP after fermentation was evaluated in the snack-type sausages. Pathogen growth (>3 Log10) was observed only during the fermentation of the snack type without a starter. The bioprotective starter prevented the growth of L. monocytogenes in the snack-type sausages and enhanced the inactivation (1.55 Log10) in fuet-type sausages, which could be related to the higher lactic acid production and consequent decrease of pH, but also the production of the antilisterial bacteriocin sakacin k. The gamma concept model allowed us to identify the main factors controlling the L. monocytogenes’ growth, i.e., the temperature during the early stages and aw at the end of the production process. The earlier acidification linked with the addition of starter culture made the interaction with the other factors (undissociated lactic acid, aw and temperature) to be the growth-preventing determinants. High-pressure processing only caused a significant reduction of L. monocytogenes in snack-type, which showed higher aw. The application of HPP after fermentation did not offer a relevant advantage in terms of efficacy. Corrective storage did not promote further pathogen inactivation. The findings of the work will guide the food industry to apply effective strategies (e.g., fermentation temperature and bioprotective starter cultures) to control L. monocytogenes in chicken dry-fermented sausages.

Growth Control of Listeria monocytogenes in Raw Sausage via Bacteriocin-Producing Leuconostoc carnosum DH25

“…Nevertheless, L. monocytogenes numbers decreased during the storage of the Mettwurst in all samples (0.73 log CFU/g DH25+St+L; 0.96 log CFU/g DH42+St+L; 1.21 log CFU/g St+L) except for the control sample L where an increase of 0.93 log CFU/g occurred. The capacity of L. monocytogenes to proliferate in raw sausage, even under refrigerated conditions, has been previously documented by various investigations [47][48][49][50][51]. For instance, Luo et al (2015) [52] conducted an experiment wherein ready-to-eat ham and sausages were inoculated with an initial concentration of 3.05 log CFU/g L. monocytogenes, leading to an ultimate cell density exceeding 8 log CFU/g.…”

“…carnosum, L. sakei. and L. plantarum is able to control the growth of the food pathogen L. monocytogenes in fermented sausage during the fermentation as well as at lower temperatures up to 2 • C during the storage of sausages [34,47,49,50,54]. Castellano & Vignolo (2006) [34] investigated the inhibition of the growth of Listeria innocua via the bacteriocin-producing Lactobacillus curvatus CRL705 in a challenge test with vacuum-packed meat stored at 2 • C for 36 days.…”

Bacteriocins and Bacteriophages as Dual Biological Players for Food Safety Applications

“…Because of their distinct mode of action, these combinations, as above stated, reduce or prevent the development of resistant bacterial strains. Moreover, bacteriocins have been reported to support various applications when tested collectively with physical treatments [41], such as high pressure [50] or pulsed electric fields [51]. Finally, the combination of bacteriocins with bacteriophages to combat foodborne pathogens continues to result in the design of promising prospective interventions to reduce foodborne bacterial disease and inhibit food spoilage [4,52,53].…”

The Antilisterial Effect of Latilactobacillus sakei CTC494 in Relation to Dry Fermented Sausage Ingredients and Temperature in Meat Simulation Media

“…The effect of NaCl, manganese (Mn) and glucose (Gluc) concentration and temperature (T) on the behaviour of L. sakei and L. monocytogenes in monoculture and coculture was evaluated through two complete factorial designs (α = 2 3/4 ), using a circumscribed Central Composite Design (CCD) [35], with three independent factors each (Table 1). The central levels of the independent factors were selected regarding the typical concentrations and fermentation temperatures employed on industrial DFS production [20,31]. A total of 40 experimental runs were designed, of which 30 were conducted.…”

“…Some LAB strains (the so-called bioprotective LAB) produce small antimicrobial peptides (i.e., bacteriocins such as sakacin and enterocin) with strong antimicrobial activity against L. monocytogenes [17] that can be used as a strategy to control the pathogen [18,19]. In fermented meat products, the bioprotective culture Latilactobacillus sakei CTC494 (formerly Lactobacillus sakei CTC494), a producer of sakacin K, has been used as starter culture in different types of DFSs, enhancing food safety due to its antilisterial effect [20,21]. The sakacin K antilisterial effect of L. sakei CTC494 has been previously tested with Listeria innocua coculture in meat simulation media [22], but it is the first time that it is experimented in coculture with the pathogenic L. monocytogenes.…”