View/Open - ARAN - National University of Ireland, Galway

Chapter 2
2. Abstract
Food-borne pathogens can attach to food contact surfaces. Bacterial
attachment and survival in food processing environments may be assisted
by the ability of the bacterial cells to form a biofilm. The biofilm may
provide a protective layer of tightly attached cells and proteinaceous
substances that shield the cells from harsh environments such as cleaning
agents or dry conditions. In 2008, there was a large outbreak of S. Agona
originating from a food processing plant. It was hypothesised that biofilm
formation may have contributed to S. Agona persistence in the
environment. This hypothesis has also been proposed in other food-borne
outbreaks.
The research described in this chapter examines the density of biofilm
formed by the S. Agona SAGOXB.0066 outbreak strains in comparison to
other S. Agona strains. The density of biofilm formed by S. Agona strains
was also compared to strains belonging to the S. Typhimurium and S.
Enteritidis serovars. In order to assess the extent to which particular
surfaces may differ with regard to their ability to support Salmonella
biofilm, five surfaces comprising of glass, stainless steel, polycarbonate, tile
and concrete were tested. All isolates form biofilm on all surfaces studied.
Based on the enumeration of removed cells, the S. Agona strain associated
with the outbreak did not result in more dense biofilm compared with
other strains of S. Agona. However, in all instances S. Enteritidis biofilm
density was lower than that of S. Agona and S. Typhimurium. The density of
biofilm was dependent on substratum as biofilm density was greater on tile
than concrete, polycarbonate, stainless steel and glass.
2.1. Introduction
It is estimated that up to 85-95% of salmonellosis cases are a result of
food-borne infection [5, 155]. During the processing and handling of
contaminated raw meat, work surfaces can become heavily colonized with
Page
37