Prevalence and biofilm-forming ability of Listeria monocytogenes in New Zealand mussel (Perna canaliculus) processing plants

► Long-term persistence Listeria monocytogenes in New Zealand mussel plants. ► Cross-contamination can be from external and internal sources. ► Persistence of isolates did not correlate with the intensity of biofilm formation. ► Matching pulsotypes between human illness in New Zealand and mussel plants. ► New Zealand isolates did not share common pulsotypes with international ones.