Control of Listeria monocytogenes in the Processing Environment by Understanding Biofilm Formation and Resistance to Sanitizers

Abstract

Listeria monocytogenes can colonize in the food processing environment and thus pose a greater risk of cross-contamination to food. One of the proposed mechanisms that facilitates such colonization is biofilm formation. As part of a biofilm, it is hypothesized that L. monocytogenes can survive sanitization procedures. In addition, biofilms are difficult to remove and may require additional physical and chemical mechanisms to reduce their presence and occurrence. The initial stage of biofilm formation is attachment to surfaces, and therefore it is important to be able to determine the ability of L. monocytogenes strains to attach to various inert surfaces. In this chapter, methods to study bacterial attachment to surfaces are described. Attachment is commonly induced by bringing planktonic cells into contact with plastic, glass, or stainless steel surfaces with or without food residues ("soil") in batch or continuous (e.g., with constant flow of nutrients) culture. Measurement of biofilm formed is carried out by detaching cells (with various mechanical methods) and measuring the viable counts or by measuring the total attached biomass. Resistance of biofilms to sanitizers is commonly carried out by exposure of the whole model surface bearing the attached cells to a solution of sanitizer, followed by measuring the survivors as described above.

Comprehensive Evaluation and Implementation of Improvement Actions in Butcher Shops

“…coli O157:H7 have the ability to attach onto stainless and other food-contact surface materials [ 9 – 11 ]. Foodstuff manufacture equipment and the surrounding environment may serve as potential reservoirs of contamination [ 12 , 13 ].…”

Listeria Occurrence and Potential Control Strategies in Alternative and Conventional Poultry Processing and Retail

“…The capability of L. monocytogenes to attach to common food contact surfaces such as plastic, rubber, stainless steel, and glass is due to their ability to produce and form biofilms (Wilks et al, 2006;Giaouris et al, 2015). Biofilms, an assemblage of microbial cells that are irreversibly associated with a surface and enclosed in a matrix of primarily polysaccharide material (Manios and Skandamis, 2014), are considered a major problem in the food processing industry. Listeria monocytogenes can attach to and survive on various working contact surfaces within these biofilms, and in this situation, they have been shown to be more resistant to biocides which increases the risk of food contamination (Manios and Skandamis, 2014).…”

“…Biofilms, an assemblage of microbial cells that are irreversibly associated with a surface and enclosed in a matrix of primarily polysaccharide material (Manios and Skandamis, 2014), are considered a major problem in the food processing industry. Listeria monocytogenes can attach to and survive on various working contact surfaces within these biofilms, and in this situation, they have been shown to be more resistant to biocides which increases the risk of food contamination (Manios and Skandamis, 2014). Out of 40 tested strains of L. monocytogenes, all produced biofilms on plastic surfaces immersed in brain heart infusion agar (Stepanović et al, 2004).…”

“…include ability to grow and survive at low temperatures, ability to elicit a survival response and undergo physiological adaptation to nutrient deprivation, competitiveness for nutrients (largely due to biofilm formation), resistance to cleaning products, random primary colonization, and over time a reintroduction of the same strain (Blackman and Frank, 1996). Biofilms can be difficult to control since they typically form where water is plentiful and cleaning is not performed properly, which can reduce the antimicrobial effects of some products (Verghese et al, 2011); (Manios and Skandamis, 2014).…”

Cross contamination of <i>Listeria monocytogenes</i> in ready-to-eat meat product during slicing: a predictive approach

“…This pathogen is the causative agent of listeriosis, a severe disease that affects immunocompromised individuals, pregnant women, the elderly and young children . Different from most pathogens, L. monocytogenes is ubiquitous and a common contaminant in the food processing environment, mainly due to formation of resistant biofilms on surfaces (Manios & Skandamis, 2014). Absence of competing microbiota in heat processed foods favors its growth (Gombas et al, 2003).…”