James S. Dickson

Attachment ofSalmonella typhimurium andListeria monocytogenes to beef tissue: effects of inoculum level, growth temperature and bacterial culture age

Abstract The effects of inoculum level, growth temperature and culture age on the attachment of Salmonella typhimurium and Listeria monocytogenes to beef tissue surfaces were evaluated. An increase in inoculum level resulted in an increase in the number of attached cells for both bacteria which was proportional to the increase in inoculum. Bacteria grown at 23°C attached in higher numbers ( P ) to fat tissue than bacteria grown at 37°C or at 37°C followed by 24 h at 5°C. Growth temperature did not affect attachment to lean tissue for either bacterium. Overnight cultures of both bacteria attached in greater numbers ( P ) to both tissue surfaces than cultures incubated for 66 h, with a difference of > 1 log 10 cycle between 18- and 66-h L. monocytogenes cultures.

Attachment ofSalmonella typhimurium andListeria monocytogenes to glass as affected by surface film thickness, cell density, and bacterial motility

SummaryWith equal cell densities, surface film thickness did not influence the numbers ofSalmonella typhimurium andListeria monocytogenes cells which attached to glass. MotileL. monocytogenes cells had a greater cell surface charge and generally attached in higher numbers than non-motile cells.