Evaluation of propidium monoazide (PMA) treatment directly on membrane filter for the enumeration of viable but non cultivable Legionella by qPCR.

A PMA (propidium monoazide) pretreatment protocol, in which PMA is applied directly to membrane filters, was developed for the PCR-based quantification (PMA-qPCR) of viable Legionella pneumophila. Using this method, the amplification of DNA from membrane-damaged L. pneumophila was strongly inhibited for samples containing a small number of dead bacteria.

Evaluation of a chromogenic medium for identification and differentiation of Listeria monocytogenes in selected foods.

Listeria monocytogenes continues to be a threat to food safety in the United States despite a "zero tolerance" policy. When Listeria species are identified by standard cultural methods, confirmation of L. monocytogenes takes days to complete.