Developing application and detection methods for Listeria monocytogenes and fish extract on open surfaces in order to optimize cleaning protocols

Abstract

a b s t r a c tSurfaces in the food industry are often fouled with bacteria and organic materials. A range of fouling and testing methods using two Listeria monocytogenes strains (Scott A and N53-1) and organic material (0.4 g/ml fish extract) were designed to determine the efficacy of two different cleaning methods (spray and wipe) in 1% sodium hypochlorite. The optimum method for applying the cells and organic material to substrata occurred when the cells and organic material were mixed together, dried onto the surface and stained. As the number of cleaning and re-foulings increased, cells were removed from the surfaces but the organic material remained. The pattern of organic material retention was different on the surfaces with the different cleaning protocols, but neither method was better at removing the retained organic material. More cells were removed from the surfaces by the spray than the spray with wipe clean.There was no difference in cell number retention for either of the L. monocytogenes strains. These findings are valid for a 'dirty material' as classified in BS EN1276. To determine cleaning method efficacy, the application of cells and organic material to a surface is important, as is the detection methods used.

Modeling the process of microbial biofilm formation on stainless steel with a different surface roughness

“…Studies into the influence of topography and roughness of surface on the microbial adhesion are rather ambiguous. Thus, according to research [23,24], there is a correlation between a surface roughness and the bacterial adhesion, with the attachment of microorganisms to the surface increasing with an increase in roughness. It is reported [17,25] that forming a biofilm occurred much slower at the surface with a roughness of up to 0.4 μm, compared with the surface roughness greater than 0.8 μm.…”

Production of hybrid macro/micro/nano surface structures on Ti6Al4V surfaces by picosecond laser surface texturing and their antifouling characteristics

“…The development of surfaces which reduce biofouling is of great interest for industrial applications [1]. Biofouling may represent a threat to public health, causing medical device failures or causing infections and diseases [2].…”

The effect of surface properties on bacterial retention: A study utilising stainless steel and TiN/25.65at.%Ag substrata

“…Possible problems associated with surface fouling and subsequent biofilm formation include potential risks to food quality, product spoilage, biodeterioration and blockages of mechanical components, and risks towards the health of the consumer (Whitehead and Verran, 2015).…”

“…In 2011, the Centres for Disease Control and Prevention (CDC) reported that foodborne disease caused a projected 48 million illnesses, 128,000 hospitalisations and 3000 deaths annually in the United States between 1996 and 2010 (Nyachuba, 2010;Schlisselberg and Yaron, 2013;Srey et al, 2013). Open work surfaces within the food industry are considered to be a potential source of microbial and organic contamination with a high risk of biotransfer between contaminated and clean products (Whitehead et al, 2015). Contamination of food produce can occur at any stage of the process (Srey et al, 2013).…”

“…The correlation between the hydrophobicity of bacteria and surfaces has been described in some works as a primary driving force in the adhesion of microbes to surfaces (Zeraik and Nitschke, 2012). Combined with the interactions with other surface parameters such as the Lewis acid-base and van der Waals forces, hydrophobicity can result in preferential bacterial attachment, adhesion and retention to surfaces (Faille et al, 2002;Whitehead et al, 2015). Although some claims have been made that bacteria which are generally negatively charged will preferentially adhere to negatively charged surfaces (Zeraik and Nitschke, 2012), there is conflicting data in this area due to assays being carried out in a number of different ways and under different environmental conditions (Chae et al, 2006;Whitehead et al, 2015).…”