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

© 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Surfaces 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

Culture Conditions of Roseobacter Strain 27-4 Affect Its Attachment and Biofilm Formation as Quantified by Real-Time PCR

The fish probiotic bacterium Roseobacter strain 27-4 grows only as rosettes and produces its antibacterial compound under static growth conditions. It forms three-dimensional biofilms when precultured under static conditions. We quantified attachment of Roseobacter strain 27-4 using a direct real-time PCR method and demonstrated that the bacteria attached more efficiently to surfaces during static growth than under aerated conditions