The tests that the U.S. government relies on to keep foods free from genetically modified contaminants can miss low levels, claims a controversial research paper by the lowa company, Genetic ID.
The tests in question use antibodies to detect the presence of GM foods. But the companies making such tests claim that the report is an attempt by Genetic ID to promote the technique it uses.
Genetic ID prepared samples of soybean containing between 0.1 and 10 per cent GM beans, and sent them to official testing labs. Of the samples with a GM content of less than 1 per cent, more than 30 percent were incorrectly identified as GM-free.
The company says it also has unpublished evidence that there are similar problems with the detection of star link maize, a GM strain not approved for human consumption because of fears that it may trigger allergies.
At least one shipment of maize destined for Japan which prohibits even traces of unapproved GM foods was cleared by the U.S. only to fail Japanese tests.
Genetic IDs researchers say that antibody tests should be supplemented by the technology the company uses, the polymerize chain reaction (PCR) method, which detects modified DNA directly. But critics disagree.
Genetic IDs report admits that the antibody tests are reliable if carried out properly, Layton says. And he points out that the labs that took part were told that the tests should be performed as they are routinely used, Labs do not generally test for levels less than 1 percent for soybeans.
So if the labs usually test for a 5 per cent level an acceptable level for soybean exports to Japan its no surprise they failed to detect a 1 percent level. All the labs reliably detected samples with a 10 percent GM content.
Don Kendall of the U.S. Department of Agriculture says the USDAs quality assessment of its own labs showed that the tests are being used correctly.
In response to Genetic IDs report, however, it is investigating further. But Kendall doesnt expect policy to be changed to include the use of PCR.
1. A primary purpose of the passage is to
A. refute a previously held practice.
B. discuss a controversial issue.
C. propose an alternative hypothesis.
D. summarize existing research.
E. question the validity of a hypothesis.
2. If the assertions in the passage are true, which of the following must also be true?
A. Polymerize chain reaction technique cannot be used in conjunction with antibody tests to detect the presence of GM foods.
B. Antibody tests are unreliable in testing for the presence of GM contaminants in foods.
C. There are no reliable methods to detect the presence of genetically modified contaminants in foods.
D. The technique used by Genetic ID to detect food for GM contaminants is acceptable for Japan.
E. Even low levels of genetically modified contaminants in the foods can be harmful.
3. Which of the following can be inferred from the passage about Japans restrictions on genetically modified foods?
A. Japan doesnt use its own tests to detect the presence of GM foods in the foods imported to the country.
B. Japan does not allow foods with a GM content below 5 percent level to be imported to the country.
C. Japan permits foods with a GM content of above 5 percent to be imported to the country.
D. Japan conducts its own tests to detect the presence of GM content in foods imported from other countries.
E. Japan is willing to buy foods from the United States that are tested using the polymerize chain reaction