Assessment of Performance of Two Rapid Methods for On-Site Control of Microbial and Biofilm Contamination

Abstract

(1) Background: The validation of hygiene procedures in food industries is paramount to ensure that food contact surfaces are properly decontaminated before production. Rapid, sensitive and reliable tools are needed for routine hygiene validation in order to increase food safety levels. Two novel tools for biofilm detection (TBF 300) and detection of low levels of microbial contamination (FreshCheck) have been assessed. (2) Methods: Biofilms of relevant food pathogens: Listeria monocytogenes and Salmonella spp. were grown for 3 and 10 days to assess the performance of the biofilm detection product. Surfaces were inoculated with different levels of L. monocytogenes to determine the limit of detection of FreshCheck. (3) Results: TBF 300 visibly stained 3 days-old biofilms of both pathogens, containing 5.0–5.4 log CFU/cm2. FreshCheck showed a positive reaction with contamination levels as low as 10 CFU/cm2 for L. monocytogenes. (4) Conclusions: Assessment of the hygienic status of food contact surfaces before production can be greatly improved with the use of the two novel tools evaluated in this study. The detection of microorganisms’ presence at very low levels of contamination as well as identification of biofilm growth spots is available in a rapid and easy way, with a big potential contribution to food safety.

Bacteriophage DW-EC with the capability to destruct and inhibit biofilm formed by several pathogenic bacteria

“…Biofilm growth was seen not covering the entire 96-well base plate (Fig. 1), similar to a previous study in which the biofilm was observed to coagulate in the center and along the 96-well plate wall 15 . On the other hand, more biofilm was formed and suspend on the media than on stainless steel (Fig.…”

“…The stainless surface is hydrophilic and has a negative charge at neutral pH. The surfaces of bacterial cells also have a negative charge, making it difficult for bacteria to colonize these surfaces 15 .…”

A Reproducible Method for Growing Biofilms on Polystyrene Surfaces: Biomass and Bacterial Viability Evolution of Pseudomonas fluorescens and Staphylococcus epidermidis

“…Despite its potential for testing antibiotic compounds in a high-throughput method, the use of 96-well microplates leads to the development of biofilms covering a quite small area with no control on the biofilm growing on the walls of the microplate. This makes a direct inspection difficult or impossible [19]. Additionally, some authors pooled together the scraped biofilm contents of three wells to have a single replicate [53].…”

“…All methods for growing biofilms have advantages and drawbacks, but the choice of a method also depends on the natural biofilm growth conditions that are mimicked. The existing methods are characterised by different static or hydrodynamic conditions influencing the conditioning, attachment, colonization and detachment of the biofilm [19]. For instance, flow cells can mimic the condition of a piping system, while a tube can be representative of a temporary storage tanks in industries [20][21][22].…”

“…Among the methods that are used to develop/seem to develop biofilms on a horizontal surface there are those employing CDC reactors and those using petri dishes and well plates. However, the formers require the laboratory to be equipped with CDC reactors and the latter do not prevent the biofilms from growing on the walls [11,19]. None of these methods are suitable to accomplish the requirements of growing the biofilms on a flat surface.…”