Effect of peracetic acid on biofilms formed by Listeria monocytogenes strains isolated from a Brazilian cheese processing plant

Abstract

This study aimed to investigate the effect of peracetic acid (PAA, 0.5%) on adherent cells of three strains of Listeria monocytogenes strains belonging to serotypes 4b and 1/2b that had been previously isolated from the environment of a Brazilian cheese plant. The assays were conducted using polystyrene microplates and stainless steel coupons and the adhered cells were treated with PAA for 60, 120 and 180 s. On stainless steel, biofilms were partially inactivated by PAA after 60 s and almost 100% of the cells were damaged within 180 s using epifluorescence microscopy with LIVE/DEAD® staining. On polystyrene microplates, PAA decreased (P<0.05) biofilm biomass produced by the three L. monocytogenes isolates at 60 s, when compared with controls (no PAA treatment). However, PAA did not completely eliminate L. monocytogenes cells on polystyrene microplates (decreasing 1.8-2.5 log cycles after treatment with PAA for 180 s). The correct concentration and contact time of PAA is critical for eliminating biofilms formed by L. monocytogenes on stainless steel surfaces, although further studies are needed for defining efficient PAA treatments to remove adherent cells of this pathogen on plastic polymers.

Enzyme-based approaches to control microbial biofilms in dairy processing environments: A review

“…However, pipe connections, valves and other places with difficult access for biocides are the main obstacles for proper cleaning of dairy processing lines, thus representing potential biofilm formation (Marchand et al, 2012). Moreover, microorganisms adhered to surfaces after biofilm formation are more resistant to biocides, such as chlorine, than non-adherent microorganisms (Lee et al, 2016(Lee et al, , 2017b.…”

“…L. monocytogenes is another pathogenic bacterium whose biofilms represent a significant problem in dairy processing areas, mainly because of the contamination of food handling surfaces, equipment and pipes (Kadam et al, 2013). Formation of biofilms of L. monocytogenes depends on several factors, such as pH, surface material for adhesion, availability of inorganic or organic matter, resistance to adhesion and temperature (Lee et al, 2017a(Lee et al, , 2017b. According to Silva and De Martinis (2013), L. monocytogenes can adhere and form biofilms at a cell concentration of 10 4 -10 7 UFC/cm 2 .…”

Aplicação de combinações enzima-sanitizante contra biofilmes de >i<Staphylococcus aureus>/i<

“…monocytogenes depende de vários fatores, como pH, material de superfície para adesão, disponibilidade de matéria inorgânica ou orgânica, resistência à adesão e temperatura (LEE et al, 2017a(LEE et al, , 2017b BRIDIER et al, 2011). Portanto, avaliações de rotina são recomendadas no ambiente da indústria de laticínios para identificar patógenos com a capacidade de produzir biofilmes em superfícies a partir de materiais comumente usados para a fabricação de produtos lácteos (LEE et al, 2014).…”

“…Além disso o HS também tem um potencial antimicrobiano contra biofilmes de S. aureus . O APA é um biocida de amplo espectro amplamente utilizado na indústria de laticínios, pois não produz resíduos tóxicos e é considerado ecologicamente correto, quando comparado a outros biocidas (LEE et al, 2017). No entanto, os microrganismos aderidos às superfícies após a formação do biofilme são mais resistentes aos biocidas, como HS e APA, do que os microrganismos não aderentes .…”

“…Porém, conexões de tubos, válvulas e outros locais de difícil acesso para biocidas são os principais obstáculos para a limpeza adequada das linhas de processamento de laticínios, representando assim a formação de biofilme potencial . Além disso, os microrganismos aderidos às superfícies após a formação do biofilme são mais resistentes aos biocidas, como o cloro, do que os microrganismos não aderentes (LEE et al, , 2017b.…”