DIFFERENTIATION OF LISTERIA-INNOCUA ISOLA TES FROM AN AUSTRIAN CHEESE-MAKING FACILITY USING A MULTIPRIMING RANDOM AMPLIFICATION OF POLYMORPHIC DNA (RAPD)-PCR TECHNIQUE

Twenty-nine Listeria isolates which originated from an Austrian cheese s making facility were investigated using a multipriming Random Amplif ication of Polymorphic DNA-procedure. 155 genetic markers were evaluat ed in the examined strains using a PAUP software package (PAUP= Phylog enetic Analysis Using Parsimony). All isolates were assigned to fiftee n RAPD groups. Eleven RAPD groups were comprised of a single isolate, three RAPD groups were comprised of two isolates and a single RAPD gro up was comprised of twelve isolates. A couple of identical strains whi ch was isolated in the facility in 1992 was not distinguished from the RAPD group XIII strains originating from 1995. The results embark on considerations that the facility was recontaminated by identical strai ns both in 1992 and 1995. This fact fits the theme that another couple of identical strains occured in January (strain 14) and July 1993 (st rain 16). These findings make strict demands upon the improvement of t he unsufficient hygienic and sanitary conditions which may have enable d the Listeria innocua strains to persistently contaminate the plant a nd the cheese products. Obviously the implemented hygienic protocols c oncerning technical standards, personnel and management of production were not reliably efficient to minimize the contamination risk of the critical production aera.