ISIS Report 16/04/07
GM Protein for Ice Cream Not Ready for Commercial Use
The advisory committee has made considerable
effort towards assuring the safety of a genetically modified ice-structuring
protein intended for use in edible ices, but large gaps still remain
Prof. Joe Cummins and
Dr. Mae-Wan Ho
This report has been submitted to the
Food Standards Agency on behalf of the Institute of Science in Society. Please
circulate widely
The Advisory
committee on Novel Foods and Processes (ACNFP) of UK’s Food Standards Agency prepared a draft opinion on an ice-structuring
preparation (ice
structuring
protein Type III HPLC 12) derived from fermented genetically modified baker’s yeast
as a food ingredient [1] following the 2006 application from Unilever Corporation
for the preparation to be used in edible ices [2].
The
ice-structuring protein was derived from a polar fish, ocean pout, and is
intended for making ice cream smoother and creamier. The GM protein, produced in transgenic bakers’ yeast
prevents large ice crystals forming
in ice cream and other frozen foods.
The initial
application was put out for public comment, and the Independent Science Panel
submitted a report recommending rejection of the application until comprehensive, long term studies have been carried out [3] (GM Protein in Ice Cream, SiS 31).
Unilever responded to the comments with information
from a new study published in 2007 [4], which has been incorporated into ACNFP’s
draft opinion. The study found no immune or allergic response in human volunteers
given an oral dose of the ice structuring preparation. However, the single-blind
placebo-controlled trial left a lot to be desired, and a number of important
questions remain unanswered.
·
The
trial involved only a small number of healthy human volunteers, 23 in the
test group, and nine in the control group.
·
The
preparation used was not purified ISP, but a crude isolate containing an unknown
assemblage of yeast proteins and sugars, which would be expected to complicate
the immune response, particularly as seven in the test group and four in the
control group had predisposition to allergy.
·
A
low dose of the ice-structuring preparation, equivalent to 16.3 mg of ice
structuring protein (ISP) was given daily for five days a week over a short
period of just eight weeks, which may well not be sufficient to fully expose
the immunogenic potential of the ISP.
·
The
preparation was given orally in a “flavoured drink” instead of in ice cream,
where the use of ISP was intended. This was a serious oversight, as the complex
of ISP and microscopic ice crystals was known to elicit immune response distinct
from the ISP; antibodies to the complex, but not the protein was found in
the ISP’s natural host species, the ocean pout, as well as the Atlantic herring
[5].
Despite these
serious shortcomings, ACNFP’s Draft Opinion [1] indicated that
there was no need for a fuller study in an animal model.
There are other
considerations that need to be taken into account.
Even if the study had been properly conducted,
and no immune response could be demonstrated as the result of oral ingestion,
that would not rule out an immune response from other routes of exposure.
Children tend to ‘wear’ ice cream by spilling it on themselves. Open sores,
bruises, or cuts provide one avenue of exposure; and dried ice
cream on skin or clothing can be inhaled
into the respiratory tract as ice cream dust. These other routes of exposure
are realistic, but there no published reports on the injection of ISP into
experimental animals. The Unilever report [4] and the 2006 report on ISP by
Food Standards Australia & New Zealand [6] both describe experiments using
monoclonal antibodies to ISP as analytical tools, indicating that the protein
itself is indeed immunogenic.
A full investigation should
be carried out on the immune response to ISP following exposure by injection, topical application and inhalation.
The inflammatory potential of the commercial ISP preparation was dismissed
[1] even though no routes of exposure to the ISP other than the oral were
studied. The ACNFP further concluded that using cod allergic
individuals in assessing the allergic potential of the ISP preparation is
representative of the fish allergic population. That conclusion is irrational
and unscientific. Cod allergy is caused by parvalbumin; ISP is unrelated to
parvalbumin and has no similarity
to the protein. Study of ISP allergy in individuals with cod allergy makes
no sense at all. Assurances from such meaningless experiments are simply misleading
the public.
Similarly, long-term studies should be done on the immunogenicity
of the ice-structuring preparation in micro ice-crystal complex.
The commercial ISP preparation
appears to be made up of 60 percent un-glycosylated ISP and 40 percent gkycosylated
ISP. Only the un-glycosylated form is active in forming micro ice crystal complex, while the glycosylated
form is non-functional [1]. Purification of the un-glycosylated away from
the glycosylated form and other contaminants should be a priority.
The committee’s recommendation
that products containing the ISP preparation should be labelled as having
been derived from yeast [1] is not sufficient; it should be labelled as having
been derived from genetically modified yeast.
Nevertheless, the Draft
Opinion [1] has gone a considerable way towards assuring the safety of ISP
and we hope that such efforts will continue.
References
1. Lidner N. DRAFT OPINION ON AN APPLICATION UNDER THE NOVEL FOODS REGULATION
FOR ICE STRUCTURING PREPARATION DERIVED FROM FERMENTED GENETICALLY MODIFIED
BAKER’S YEAST Saccharomyces cerevisiae AS A FOOD INGREDIENT Draft issued for
public comment, 2April 2007 ADVISORY COMMITTEE FOR NOVEL FOODS AND PROCESSES,
http://www.food.gov.uk/multimedia/pdfs/icedraft.pdf
2. Lewis S. Application for the Approval of Ice Structuring Protein Type III
HPLC preparation for use in Edible Ices. Safety and Environmental Assurances
Centre Unilever Colworth 2006, http://www.food.gov.uk/multimedia/pdfs/ispapplication1.pdf
3. Cummins. J, Ho MW and Hooper M. GM protein in ice cream Science
in Society 31 , 9, 2006.
4. Crevel RW, Cooper KJ, Poulsen LK, Hummelshoj L, Bindslev‐Jensen C,
Burks AW and Sampson HA. Lack of immunogenicity of ice structuring protein type
III HPLC12 preparation administered by the oral route to human volunteers. Food
Chem Toxicol. 2007, 45(1),:79-87.
5. Verdier JM, Ewart KV, Griffith M and Hew CL. An immune response to ice
crystals in North Atlantic fishes. Eur J Biochem. 1996, 241(3), 740-3.
6. Food Standards Australia New Zealand A Safety Assessment Report Ice Structuring
Protein as a processing aid for ice cream and edible ices, 2006, http://www.foodstandards.govt.nz/_srcfiles/NO%2042%20Ice%20structuring%20protein%20Technical%
0Report%20_3_.pdf
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