[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[SANET-MG] your ice cream may be fishy
It is needless to say, fishy ice cream that is smooth but unlabeled may
be swamping the Amercan market!
June 26, 2006
Prof. Joe Cummins
Recombinant Pout Fish Protein in Ice Cream
Unilever is seeking approval of a recombinant ice structuring protein
derived originally from a polar fish, ocean pout, for use in making ice
cream smoother and creamier. The recombinant protein is produced using
fermentation technology based on transgenic bakers’ yeast. Ice
structuring protein protects the Pout fish in freezing waters and acts
to prevent ice crystal formation in ice cream and other frozen food. The
Unilever proposal to the UK Food Standards Agency (FSA) is presently
open for public comment (1). Previously Unilever petitioned the United
States Food and Drug Administration (FDA) to obtain the Generally
Recognized As Safe (GRAS) status for the food additive (2). Food
Standards Australia New Zealand was later petitioned by Unilever (3).
The Unilever petition to FSA is similar to the earlier petitions to FDA
and Food Standards Australia New Zealand. The recombinant Pout protein
produced in yeast was designated ISP Type III HPLC 12 glyco –ISP , the
preparation tested by Unilever contained peptides from yeast, sugars
along with the recombinant protein. A subchronic feeding test of the
preparation was conducted on rats by oral gavage for 13 weeks. A battery
of genotoxicity tests were conducted and proved to be negative. A
program of testing was undertaken. These included the kinds of allergy
tests suggested by the World Health Organization along with serum tests
of serum obtained from a few people allergic to fish. The report
stressed that the recombinant protein was identical to protein found in
edible fish (however, that kind of statement is not entirely true as
will be discussed below).(1).
There is a voluminous literature on antifreeze glycoproteins ,
particularly the proteins from polar fish. There are four main types of
glycoproteins each differing significantly from the others. The type III
proteins are around 6500 daltons in size, and they form a beta-sandwich
structure, they appear only in ocean pout( 4). There is a strong immune
response to the micro ice crystals complexed with antifreeze protein
circulating in the blood of ocean pout. The response shows that the fish
have an immune response to the ice crystals circulating in their blood
which function as conventional antigens. (5).
The recombinant protein obtained from transgenic yeast was obtained from
a synthetic gene was an altered approximation of the Pout ice
structuring gene. The code sequence was altered to facilitate active
production of protein in yeast. However, the amino acid sequence was
identical to the pout fish protein. Multiple copies of the synthetic
gene were inserted into the yeast chromosomes to accommodate greater
synthesis of the ice structuring protein (1). Production of proteins in
yeast destined for human consumption or therapy is fraught with the
problem of secondary modification of the animal or human proteins by
glycosylation or other modifications that lead to the human (or animal)
immune system recognizing the yeast modified proteins as antigens.
.There has been progress in “humanizing” the glycosylation patterns of
proteins produced in yeast and some success has been achieved (6,7)
.However, there is no evidence that there has been any effort to
“humanize” the glycosylation pattern of the ice structural protein
produced in the yeast strain used to produce the protein.
Since there has been cursory studies on the allergenicity of the
Unilever ice structural protein and that protein is used in ice cream
sold elsewhere can we assume that there is no problem? It is worth
pointing out that the use of the transgenic protein in ice cream has not
been labeled so any resulting problems from its use may go unrecognized.
For example, transgenic expression of a bean gene in peas resulted in
altered immunogenicity leading to debilitating even fatal lung
inflammation. That response was related to the glycosylation pattern of
the transgenic protein (8). The inflammatory response did not appear to
have been studied in the Unilever application even though there was
every indication from the scientific literature that pouter ice
structural protein is immunologically active.
In conclusion, contrary to the claims of Unilever the ice nucleation
protein does not appear to be identical to the protein produced in
pouter fish. The transgenic protein seems to bear the glycosylation
pattern of yeast making that protein a unique antigen. Even though
allergenicity was studied in a cursory way there is clear precedent for
studying inflammation before exposing the European people to the
transgenic ice cream.
1. Lewis,S. Application for the approval of ice structuring protein
typ III HPLC12 preparation for use in edible ices Safety and
Assurance Centre 2006 http://www.acnfp.gov.uk/assess/fullapplics/isp
2. US Food and Drug Administration Agency Response Letter GRAS Notice
No. GRN000117 2003 http://www.cfsan.fda.gov/~rdb/opa-g117.html
3. Food Standards Australi New Zealand Initial Assessment Report
Application A544 Ice Structuring Protein as a Processing Aid for
Ice Cream and Edible Ices
4. Harding MM, Anderberg PI and Haymet AD 'Antifreeze' glycoproteins
from polar fish. Eur J Biochem. 2003 Apr;270(7):1381-92
5.Verdier JM, Ewart KV, Griffith M and Hew CL. An immune response to ice
crystals in North Atlantic fishes. Eur J Biochem. 1996 Nov ;241(3):740-3
6. Wildt S and Gerngross TU. The humanization of N-glycosylation
pathways in yeast. Nat Rev Microbiol. 2005 Feb;3(2):119-28
7. Li H, Sethuraman N, Stadheim TA, Zha D, Prinz B, Ballew N, Bobrowicz
P, Choi BK, Cook WJ, Cukan M, Houston-Cummings NR, Davidson R, Gong B,
Hamilton SR, Hoopes JP, Jiang Y, Kim N, Mansfield R, Nett JH, Rios S,
Strawbridge R, Wildt S and Gerngross TU. Optimization of humanized IgGs
in glycoengineered Pichia pastoris.
Nat Biotechnol. 2006 Feb;24(2):210-5
8. Prescott VE, Campbell PM, Moore A, Mattes J, Rothenberg ME, Foster
PS, Higgins TJ and Hogan SP. Transgenic expression of bean alpha-amylase
inhibitor in peas results in altered structure and immunogenicity. J
Agric Food Chem. 2005 Nov 16;53(23):9023-30
To unsubscribe from SANET-MG:
1- Visit http://lists.sare.org/archives/sanet-mg.html to unsubscribe or;
2- Send a message to <firstname.lastname@example.org> from the address subscribed to the list. Type "unsubscribe sanet-mg" in the body of the message.
Visit the SANET-MG archives at: http://lists.sare.org/archives/sanet-mg.html.
Questions? Visit http://www.sare.org/about/sanetFAQ.htm.
For more information on grants and other resources available through the SARE program, please visit http://www.sare.org.