Yes, this question of the risk to human health of using salt containing YPS
as an additive is becoming a saga, particularly as John Wekell's message as
long ago as March 28 pointed to a negligible risk from cyanide derived from
the additive. Marion's original message concerned the risk from the cyanide,
but later messages from her raised questions about the safety of the
additive itself. A difficulty in dealing with Marion's queries is that she
provides no information about the product or process she has in mind, and
she does not seem to have any data on either YPS or cyanide in her products.
She does not even state if YPS is present in the salt she uses in the
process. Without this information it is not possible to conduct a specific
risk analysis, but, as correspondents have pointed out, on reasonable
assumptions the risk from the additive or the cyanide is extremely low or
not present. At the expense of repeating some that has already gone before,
let me approach this from the hazard and risk aspects of a HACCP procedure.
In the following discussion I am using the terms hazard and risk as defined
in National Advisory Committee on Microbiological Criteria for Foods (1998).
Principles of risk assessment for illness caused by foodborne biological
agents. Journal of Food Protection, 61, 1071-1074: Hazard: A biological,
chemical, or physical agent in, or property of, a food that may cause a food
to be unsafe for consumption; Risk: The likelihood that an adverse effect
will occur within a population as a result of a hazard in a food.
Marion has identified two hazards: YPS, and cyanide derived from the YPS. I
have not made a search of the toxicology literature for toxicological
information on YPS, and anyway, I would not be able to evaluate the
literature adequately. It is a permitted food additive in the USA and in
Europe at least; the information has already been referred to in this thread
and I have to assume the risks to health have been evaluated by experts. In
a assessment of hazards and risks for a HACCP plan the fact that a substance
is listed as a food additive would be equivalent of seeking advice from
experts. There seems to be some risk because a limit is applied to its use,
but there is nothing sinister in that; many chemicals, including common
salt, are toxic if used in excessive amounts. I conclude the risk to human
health in using YPS in salt within the limit set by regulation has no
unacceptable risk.
There is a review of the toxicity of cyanide at the Oak ridge National
Laboratory site: http://risk.lsd.ornl.gov/tox/profiles/cyanide There
certainly seems a high probability that cyanide will be present in fish
which has been salted by YPS-containing salt. In the absence of data on
cyanide contents of Marion's products, a worse case scenario can be used.
This has already been done by previous correspondents, but let me repeat it
to make this message complete. I will use the permitted limit of 20 mgYPS/kg
salt listed in EU Council Directive 95/2/EC of 20 February of 20 February
1995. This is expressed as anhydrous potassium ferrocyanide. On a molar
basis is higher than the 13 mg/kg of the anhydrous sodium ferrocyanide
permitted by the US regulation so represents more of a worse-case scenario.
Paul Taylor's assumption of 3% salt, wet weight, is reasonable as the salt
content at the higher end of smoked fish products; typical of smoked salmon.
Marion raised the question of diffusion of YPS into fish flesh compared with
salt. I would be surprised if this has been measured, (there isn't a great
deal of data on diffusion of salt in fish flesh), but at a guess I would
think it would be slightly slower that NaCL so I believe am on the safe side
by assuming it diffuses at the same rate. Anhydrous potassium ferrocyanide
contains 42.4% cyanide. Let's assume a larger portion, 150g, than Paul did -
consumption by a smoked salmon addict. Then the portion will contain 4.5g of
salt, 0.09 mg of YPS and, if all the cyanide is liberated, 0.038mg of
cyanide. Toxicologists typically express doses of toxicants on a kg body
weight basis and assuming a small person weighing 45 kg, (rather than myself
at 95kg), this intake is 0.00084 mg cyanide/kg. Robert LaBudde in his
message of 23 April quotes a FAO/WHO acceptable daily in take of 0.025
mg/kg, so the intake from the smoked fish on the basis of this scenario is
well below the FAO/WHO guidelines and I assume poses not risk to health.
Marion also raised the question, 2 May, of the 'attraction' of metals such
as lead and mercury in treated fish tissue. This is a matter of chemistry
and Marion could find this out by consulting appropriate texts, but I am not
clear from where these metals would be attracted. I do not see this as a
hazard at all.
My conclusion is the same as other correspondents - there is no appreciable
risk to human health of using salt containing YPS as an additive within
regulatory limits. Perhaps Marion would care to conduct her own risk
assessment and let us know her conclusions. If she considers any risk is not
acceptable, then the remedy is simple - use salt that does not contain the
additive.
Peter Howgate
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