Survival of Salmonella on a Polypropylene Surface under Dry Conditions in Relation to Biofilm-Formation Capability

Abstract

This study was conducted to gain insights into the survival of Salmonella on a polypropylene surface in relation to the ability of these bacteria to form a biofilm. We selected Salmonella strains known for the relative ease or difficulty with which they formed biofilms based on microtiter plate assays and studied the survival of these strains on polypropylene discs in a desiccation chamber by sequentially counting CFUs. The biofilm-forming strains survived longer on the plastic disc surface than did biofilm-deficient strains. The biofilm-forming strains remained at over 10(4) CFU per plate until day 175, whereas the biofilm-deficient strains decreased to below 10(2) CFU per plate on day 20 or below 10(4) CFU per plate on day 108. Extracellular materials on the polypropylene surface were observed by scanning electron microscopy and crystal violet staining for the biofilm-forming strains but not for the biofilm-deficient strains. The extracellular polymeric materials on the polypropylene surface may have protected the bacterial cells from dryness, although the possibility of some inherent resistance to environmental stresses linked to biofilm formation could not be excluded. These results indicate that Salmonella strains with high biofilm productivity may be a greater risk to human health via food contamination by surviving for longer periods compared with strains with low biofilm productivity.

The two-component system PrlS/PrlR of Brucella melitensis is required for persistence in mice and appears to respond to ionic strength

“…This behaviour related to 'biofilm' formation could promote bacterial survival when faced with desiccation by maintaining a hydrated microenvironment, even if inherent resistance linked to biofilms cannot be ruled out (Iibuchi et al, 2010). Importantly, Brucella spp.…”

Attachment and Biofilm Formation by Salmonella in Food Processing Environments

“…Interestingly, inoculation onto fresh-cut produce surfaces, as well as onto inert surfaces, such as polyethersufone membranes, was found to significantly increase the survival of salmonellae during otherwise lethal acid challenge (pH 3.0 for 2 hours) (Gawande & Bhagwat, 2002). Similarly, Salmonella strains with high biofilm productivity survived longer on polypropylene surfaces under dry conditions than strains with low productivity (Iibuchi et al, 2010). In the food processing environments, food-contact surfaces come in contact with fluids containing various levels of food components.…”

“…Interestingly, salmonellae have been shown to survive for extended periods of time in nonenteric habitats, including biofilms on abiotic surfaces . Thus, several reports have demonstrated the ability of Salmonella to form biofilms on abiotic surfaces outside the host, such as stainless steel (Austin et al, 1998;Chorianopoulos et al, 2010;Giaouris et al, 2005;Giaouris & Nychas, 2006;Hood & Zottola, 1997a,b;Joseph et al, 2001;Kim & Wei, 2007, 2009Møretrø et al, 2009), plastic (Asséré et al, 2008Iibuchi et al, 2010;Jain & Chen, 2007;Joseph et al, 2001;Ngwai et al, 2006;Stepanović et al, 2003Stepanović et al, , 2004Vestby et at., 2009a,b), rubber (Arnold & Yates, 2009), glass (Kim & Wei, 2009;Korber et al, 1997;Prouty & Gunn, 2003;Solano et al, 1998), cement (Joseph et al, 2001), marble and granite (Rodrigues et al, 2011). Taken into account, that all these surfaces are commonly encountered in farms, slaughter houses, food industries and kitchens, it is obvious that the risk for public health is quite serious.…”

Bacillus cereus growth and biofilm formation: the impact of substratum, iron sources, and transcriptional regulator Sigma 54

“…EPS produced by biofilm formers may provide protection against desiccation, as shown for Salmonella (Iibuchi et al 2010) and Acinetobacter baumannii (Espinal et al 2012). Extended survival up to 175 days for the cells of biofilm forming strains of Salmonella has been reported (Iibuchi et al 2010).…”

“…Extended survival up to 175 days for the cells of biofilm forming strains of Salmonella has been reported (Iibuchi et al 2010). In practice, wet, nutrient rich conditions, and dry conditions may alternate and affect biofilm formation.…”