Hello Mary: Both TVN and histamine are used to measure the quality and
to differentiate the quality of faq and super prime fishmeals. The
histamine content will vary by species as you mentioned. The TVN in the
fishmeal is a rough estimate of the quality of the raw material plus
solubles add back. Some TVN is flashed off in the dryer so you don't have an
exact measure of what the raw fish quality was. The market, however, does
use these 2 measurements for determining the quality of the fishmeal.
The method used to determine TVN in fishmeal is the IFOMA recommended method
based on the AOAC method. This is the ammonia nitrogen method or
distillation with Magnesium Oxide. Instead of calculating the result as %
ammonia nitrogen it is calculated as mg tvn/100 gms sample. S0 120 tvn
(mg/100 g) is actually 0.12% ammonia nitrogen.
If you go to the IFOMA web site www.ifoma.com and click on the fishmeal
analysis section and then go to tvn you will find the method description and
number.
If you need something further on this let me know. By the way, which
factory are you located at? I've visited some of the Hyduk plants over the
last few years.
Regards
Tony Bimbo
55 Cedar Lane, P. O. Box 1606
Kilmarnock, VA 22482-1606
Phone 804-435-3915
Fax 804-435-7422
E-Mail apbimbo@crosslink.net
----- Original Message -----
From: "MARY LEON" <mleon@hayduk.com.pe>
To: <seafood@ucdavis.edu>
Sent: Monday, August 21, 2000 11:07 AM
Subject: TVN and histamine
Hi group!
I´d like to know, what do you think about the TVN or TVBN like freshness
control specially for canned and frozen process, and about your experience
in the relationship between TVN and histamine in fishmeal, in some cases we
had gotten fishmeal samples with the same TVN 100-120 mg/100gr but with
histamine in wider range of variation, although samples were from the same
specie; we know there are species with less histidine, and find TVN high
and histamine low.
I believe the TVN should be use only like indicator between others, and not
take this value to determinate fishmeal quality, probably the final use
could be the justification.
Finally maybe someone has information how was determinated TVN =120 mg/100gr
like limit in prime fishmeal.
Thanks for help me.
María León
This archive was generated by hypermail 2b29 : Mon Aug 21 2000 - 11:03:35 PDT