Listeria monocytogenes-carrying consortia in food industry. Composition, subtyping and numerical characterisation of mono-species biofilm dynamics on stainless steel

Abstract

In order to find out how real Listeria monocytogenes-carrying biofilms are in industrial settings, a total of 270 environmental samples belonging to work surfaces from fish (n = 123), meat (n = 75) and dairy industries (n = 72) were analysed in order to detect L. monocytogenes. 12 samples were positive for L. monocytogenes and a total of 18 different species were identified as accompanying microbiota in fish and meat industry. No L. monocytogenes was found in samples from dairy industry. Molecular characterisation combining results of AscI and ApaI macrorestriction PFGE assays yielded 7 different subtypes of L. monocytogenes sharing in 71.43% of cases the same serogroup (1/2a-3a). Results from dynamic numerical characterisation between L. monocytogenes monospecies biofilms on stainless steel (SS) using MATLAB-based tool BIOFILMDIVER demonstrated that except in isolate A1, in which a significant increase in the percentage of covered area (CA), average diffusion distance (ADD) and maximum diffusion distance (MDD) was observed after 120 h of culture, no significant differences were observed in the dynamics of the rest of the L. monocytogenes isolates. Quantitative dual-species biofilm association experiments performed on SS indicated that L. monocytogenes cell counts presented lower values in mixed-species cultures with certain species at 24 and 48 h compared with mono-species culture. However, they remained unaltered after 72 h except when co-cultured with Serratia fonticola which presented differences in all sampling times and was also the dominant species within the dual-species biofilm. When considering frequency of appearance of accompanying species, an ecological distribution was demonstrated as Escherichia coli appeared to be the most abundant in fish industry and Carnobacterium spp. in meat industry.

Removal of Listeria monocytogenes dual-species biofilms using combined enzyme-benzalkonium chloride treatments

“…Listeria monocytogenes A1 and Escherichia coli A14 were isolated from a fish processing plant in a previous survey (Rodríguez-López et al 2015). Pseudomonas fluorescens B52, a strong biofilm former and associated with milk and dairy products spoilage, was kindly provided by Dr. Carmen San José (Allison et al 1998).…”

“…Moreover, this microorganism is well known to survive for long periods attached to food industry surfaces (Borucki et al 2003;Carpentier & Cerf 2011) as part of multi-species sessile communities (Carpentier & Chassaing 2004;Rodríguez-López et al 2015).…”

“…Inocula preparation was performed following a modification of a protocol previously described (Rodríguez-López et al 2015). Briefly, cultures were adjusted to Abs700 = 0.1 ± 0.001 in sterile phosphate buffer saline (PBS) using a Cecil3000 scanning spectrophotometer (Cecil Instruments, Cambridge, England), corresponding to a concentration of about 10 8 CFU/ml.…”

Presence ofListeria monocytogenesin Prepared Foods: Analysis of Influencing Factors

“…; Rodríguez‐López et al . ). Epidemiological data obtained in Spain indicate an incidence of foodborne listeriosis of 0.1% between years 2004 and 2007.…”

Occurrence of Listeria Species in Processing Equipments, Units and Frozen Fish of Fish Processing Factories

“…in food processing plants (Korsak et al, 2012;Campdepadrós, et al, 2012;Almeida et al, 2013;Strydom et al, 2013;Martin et al, 2014;Ortiz et al, 2014;Ruckeri et al, 2014;Rodriguez-Lopez et al 2015). There are a few studies made about the presence of L. monocytogenes in fish processing factories in the other countries (Duarte, et al, 1999;Miettinen and Wirtanen, G 2006;Skara et al, 2011).…”