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Allergenic GM Papaya Scandal

How Prof. Joe Cummins uncovered the great scandal of how US regulatory agencies approved a GM papaya even though it carries a viral gene known to be a potential allergen.

Recently the United States regulatory bodies - Department of Agriculture, Animal and Plant Health Inspection Service (USDA, APHIS), the Environment Protection Agency (EPA) and Food and Drug Administration (FDA) – united in approving the commercial production of ‘Sunset’ transgenic papaya that’s resistant to papaya ringspot virus. It is modified with a gene for papaya ring spot virus coat protein, the expression of which prevents the virus from replication by silencing the virus’ own gene [1].

The possibility that genetically modified (GM) crops may introduce novel allergens has been raised by many critics, and as part of the approval process, potential allergens have to be identified before the crops are released commercially. But the GM papaya was approved despite a recent report [2] showing that the papaya ringspot virus coat protein is a potential allergen because it contained a string of amino acids identical to a known allergen.

The US General Accounting Office (GAO) Report to Congress on Genetically Modified Foods [3] assured Congress and the public that the regimen of safety tests submitted to the FDA are adequate. "Companies that may wish to submit new GM foods for FDA evaluation perform a regimen of tests to obtain safety data on these foods, the degree of similarity between the amino acid sequences in the newly introduced proteins of the GM food and the amino acid sequences in known allergens, toxins, and anti-nutrients." GAO believed that when the sequence of a transgenic protein is found to be similar to that of allergens, further studies would be carried out, at the very least, before the GM crop or product is commercially released.

I contacted James Maryanski of the FDA by e-mail on 22 January, to alert him of the allergenic potential of the papaya virus coat protein and the relevant publication. In his reply (27 January), he wrote,

"FDA and EPA are aware of this recently published paper, though we have not had an opportunity to fully assess the findings of the paper. FDA is conducting a review of available scientific literature and intends to use this information to prepare draft guidelines for industry. Please note that the traits used to confer resistance to viral disease in papaya are pesticidal traits (plant incorporated protectants) regulated by EPA, not by FDA."

So, I was sent off to EPA, and guess what I found. The EPA’s public information stated that coat protein of papaya ringspot virus and the genetic material necessary for its production had been granted "an exemption from the requirement of tolerance" [4] in 1997, which essentially means it is exempt from safety assessment, based on the belief that the material was safe for consumption by humans and animals. No mention was made of recent study on the amino acid sequence of the virus protein. For its part, the USDA APHIS also awarded Sunset Papaya a non-regulated status [5] in 1996, because the reviewers believed that the GM crop was not harmful.

These bureaucrats remind me of the old jive doggerel by J. Cramer and J. Whitney, Ain't Nobody Here But Us Chickens,

"One night Farmer Brown was takin’ the air
Locked up the barnyard with the greatest of care
Down in the henhouse somethin’ stirred
When he shouted, "Who's There?", this is what he heard
There ain’t nobody here but us chickens, there ain’t nobody here at all
So calm yourself, stop that fuss, ain’t nobody here but us
There ain’t nobody here but us chickens, there ain’t nobody here at all"

GAO seems to be woefully misinformed about the safety assessment of GM crops, and may have modeled itself after giant accounting corporations such as RD Anderson.

This is a wakeup call for Congress and the public everywhere, who may have been misled into believing that GM food is the most strictly regulated of all foods, and that the US regulatory system is the best in the world.

  1. Tennant P, Fermin G, Fitch M, Manshardt R, Slighton J and Gonsalves D. Papaya ringspot resistance of transgenic Rainbow and SunUp is affected by gene dosage, plant development, and coat protein homology. European Journal of Plant Pathology 2001, 107, 645-53.
  2. Kleter G and Peijnenburg A. Screening of transgenic proteins expressed in transgenic food crops for the presence of short amino acid sequences identical to potential, IgE-binding linear epitopes of allergens. BMC Structural Biology 2002, 2, 8-19.
  3. United States General Accounting Office Report to Congressional Requesters "Genetically Modified Foods" GAO-02-566 May 2002.
  4. Rules and Regulations. Coat protein of Papaya Ringspot Virus and the Genetic Material Necessary for its Production; Exemption From the Requirement of a Tolerance. Federal Register August 22,1997 62, 44572-75.
  5. USDA-APHIS Petition 96-051-01P for the determination of nonregulated status for transgenic sunset papaya Lines 55-1 and 63-1 Finding of No Significant Impact September 1996.

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