Dear Richard and friends:
Unfortunately there are not enough information about the real risk of some Vibrionaceae species in infecting human beings from seafood sources. Well, there are some FDA regulations for Vibrio cholerae (Presence), V. vulnificus (presence), and V. parahaemolyticus [levels equal to or greater than 1 x 104/g (Kanagawa positive or negative).] but nothing about other vibrionaceas, like V. alginolyticus, V. mimicus, Aeromonas hydrophila, etc, etc. Remember that Vibrionaceas are naturally found in shellfish and the clinical significance relies on strain pathogenicity, infective dose, and the host's susceptibility.
On the other hand, I´ve just finished a small study about bacterial contamination of a typical peruvian seafood, which is prepared with raw conchas negras (Anadara tuberculosa). We identified Three pathogens in our 35 samples: Aeromonas hydrophila (5/35), Vibrio alginolyticus (3/35), and V. parahemolyticus (1/35), 9 out of 35 samples had at least one pathogen. So, the prevalence of pathogens was 29%, and only one sample was contamined by two pathogens (V. alginolyticus and A. hydrophila). Furthermore, in other study in other seafood dish (cebiche : prepared with either raw fish or shellfish), we found V. cholerae, Vibrio cholerae non 01 non-0139, V, alginolyticus, Aeromonas hydrophila, and V. fluvialis, which is demonstrating how frequent these pathogens may are present in seafood.
If you get a vibrionaceae strain, it will be necessary to do additional lab studies in order to know its real pathogenicity. So for better characterization of the Vibrios, species should be undertaken in isolates from shellfish, regarding virulence factors, to distinguish pathogenic from non-pathogenic forms and to contribute to the determination of risk profiles and risk assessment for each pathogen (Ristori et al., 2007)
Regards,
Victor
________________________________
From: owner-seafood@ucdavis.edu [mailto:owner-seafood@ucdavis.edu] On Behalf Of Richard Chivers
Sent: Thursday, December 06, 2007 2:42 PM
To: seafood
Subject: Vibrio spp in scallops
I am seeking information on Vibrio for risk assessment purposes. My clients recently had Vibrio spp identified in an export consignment of chilled scallops (Pecten maximus) going from the UK to Italy. We can not get information about the cfu's and the Italian vets will not identify the species.
Our HACCP identifies Vibrio as being a low level risk as the product is to be cooked before eating, large numbers are needed for infection, the organisms themselves are not common in UK waters (normally needs 15C). I have references from FAO and other sources.
What I would like to hear of are the experiences of others with this organism in a low risk food. Our problem is that the Italians, naturally, want confidence that Vibrio is not a significant hazard whilst my clients cannot test very batch prior to export.
Vibrio has not previously been considered a significant risk in UK raw fish. Furthermore EU Reg 2073/2005 has no limits for Vibrio, but comments that:
'Currently available scientific data do not support setting specific criteria for pathogenic V. vulnificus and parahaemolyticus in seafood'
and recommend that:
'There is a need for development of reliable methods for other microbial hazards too, e.g. Vibrio parahaemolyticus.'
Are there any other standards that are applied to Vibrio in other parts of the world?
Many thanks
Richard Chivers
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