SUMMARY:Autoclaved sea water and water removed from the shell cavity of mussels supported the growth of coli‐aerogenes bacteria. Attempts to reproduce conditions which had favored multiplication of coli‐aerogenes bacteria in purified mussels failed.‘Enrichment’ of sea water by repeated re‐use for storage of successive lots of mussels, in conjunction with sand filtration and aeration under conditions equivalent to 60 weeks of approved purification, did not promote the growth of coli‐aerogenes bacteria.A culture ofSalmonella typhiandSalm. paratyphiB survived for a few days only in sea water favourable to the slow multiplication ofBacterium