Microbial contamination
of meat during slaughter ts unavoldabl~.
The adhesion of two species of alterating flora, Pseudomonas frugt and Brochothrtx thermosp~~ct~, were studied. These strains adhered readily and mstantaneously to lean and fat beef tissue. The adherent populatton of the two strams of R,frugl was larger than that of B. thermosphacta.
Attachment
was not affected by pl_I vartation (5.8-7.2). Pseudomonasfragt attachment was time dependent between 1 and 10 mm, unlike that of B. thermosphactu. To determine the influence of electrostatic interactions on bacterial adhesron to meat. we studied surface charges by measuring the electrophoretic mobility and bacterial attachment in relatton to the ionic strength of the attachment medmm (0.15 M and 0.0015 M phosphate-buffered sahne (PBS)). Usmg the low tome strength medium (00015 M PBS), electrostatic interactIons were repulsive and reduced bactertal attachment to lean beef tissue, unlike that whmh was observed for fat tissue. Using the high ionic strength medium (0 15 M PBS), a medium similar to that of meat intersttttal fluids, electrostattc mteracttons seem negligible. Thus, in future studies. the thermodynamic and spectfic interactions will be investrgated.