[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.

Reference

  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
     <http://www.cfsan.fda.gov/%7Erdb/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

2004 http://www.foodstandards.gov.au/_srcfiles/A527_Dimethyl_ether_IAR_FINAL.pdf

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 <listserv@sare.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.