This study concerns the seasonal variation of bacteria in seawater and
mussels harvested from a Moroccan coastal area subject to clandestine
shellfishing. The changes in the level of bacterial counts of mussels
from harvest to sale are also presented. Both seawater and mussels sh
owed regular increases in bacterial loads from fall to summer. Freshly
harvested mussels and market mussels were the most contaminated, whil
e freshly shucked mussels, obtained by removing shells after heating s
hellstock, were the least contaminated. Heating, traditionally used to
remove shells, was found to reduce the initial bacterial loads by 72%
. However, the storage of shucked mussels for 6 to 8 h at ambient temp
eratures prior to marketing resulted in an increase in the number of b
acteria either due to recontamination or by growth of survivors. Thus,
market mussels were 20 to 86 times more contaminated than shellstock
and shucked mussels, respectively. No human pathogens were found, but
several species of marine vibrios were identified.