Transparency's picture
How did the biotech industry decide that ‘90-days’ would be the norm, or the standard time-frame for testing? And how does that fit in with the universally accepted understanding that disease and pathology often takes many months, sometimes years to develop?

A:Expert Answer

As with any trial and error testing, there must of course be a starting point and an endpoint where data can be accumulated and tested. While there is nothing in the literature citing specifically why 90 days has been established as a testing period, as in any testing protocol a baseline must be established and data collected over a period of time. This generally results in changes over a period of time during the testing period. But at some point there the law of diminishing returns sets in and additional testing results becomes insignificant to a study’s outcome. It is logical to assume that 90 days has become that standard period of testing in animal feeding studies. According to EFSA (European Food Safety Authority), “90-day animal feeding studies are often used to provide information for the risk assessment of food and feed and/or of individual substances contained therein.” 

A recently published research paper in the journal New Biotechnology suggested that longer term testing rather than the classical 90-day studies be performed on a case by case basis, and should not be the norm. The authors concluded that “long-term and multigenerational studies should only be conducted in a case-by-case approach for GE food/feed safety and nutritional regulatory assessment if some reasonable doubt remains after the 90-day rodent feeding trial.”  In fact, based on their research none of these longer-term assessments “have raised new safety concerns [regarding] marketed GE crop varieties.” They conclude that the data “does not provide evidence that more food safety testing is necessary for GE crop varieties.” In fact they claim that longer term multigenerational data could actually lower the risk assessment of GE crop varieties. And finally, the researchers proclaimed that governments are trying to “demonstrate environmental risks for cultivation of GE crops” which “fail to provide scientifically valid data.”

Additionally, I am not in agreement that it is universally accepted that “disease and pathology often takes many months, sometimes years to develop.”  Changes in cell structure and blood cells occur rather quickly when exposed to pathogens. This effect should not be confused with the diagnosis of such cellular abnormalities which are oftentimes not discovered for possibly months or years later when symptoms from these mutations actually begin to surface. 

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Hiya's picture

I have been long curious about it, too. To tell GMO is really safe enough, they should do longer study with confident.

MagickBeans4's picture

People have been the test subject for years. And cancer is at its worst.
This is what they want though.

Community Manager's picture

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Transparency's picture

Thank you for answering my question. I agree with much of what you have to say. In response to your comment, “Changes in cell structure and blood cells occur rather quickly when exposed to pathogens,” – yes, that makes perfect sense. No doubt microscopic cellular changes can and do occur rapidly.

I am definitely no scientist. However, when I use the word “disease”, I refer not just to cellular changes quickly occurring in response to pathogens, but also to a named condition manifested, over a period of time, by distinguishing signs and symptoms. For example, the 2013 Merriam-Webster dictionary defines disease as “a condition of the living animal or plant body or of one of its parts that impairs normal functioning and is typically manifested by distinguishing signs and symptoms.” So in that sense, skin cells damaged or altered by the sun might take years to develop into lesions, or the disease called melanoma. Or a seemingly healthy individual could have HIV, which could then take years to develop into “signs or symptoms” of the full-blown disease called AIDS.

How is the issue of semantics relevant to GMOs? Well, we don’t know what we don’t know, if we don’t take the time to know. The precautionary principle seems to have fallen by the wayside. In other words, if the biotech industry believes long-term testing is generally unwarranted, and scientists are confident they know everything there is to know about genes and the safety of transgenics under the convenient umbrella of “substantial equivalence”, then that makes me a little nervous -- I would venture to guess that what we know about genes and their myriad functions is just the tip of the proverbial iceberg. (Maybe when science proves itself by unraveling the mystery of junk DNA, then I will stop questioning.)

90 days as the standard period of testing may be fine as the norm. But it does concern me there are few or no major, independent, reputable, peer-reviewed, long-term GMO studies in existence…at least not many that I am aware of. I hope I am wrong.

Community Manager's picture

Building on Harold’s response - Alison van Eenennaam, Ph.D., Cooperative Extension Specialist, Animal Genomics and Biotechnology, Department of Animal Science, UC Davis, published a review on the costs and benefits of regulatory evaluations for GMOs in animal agriculture (see:, the 90-day protocol for the biotech industry was adapted from the OECD guidelines for testing health effects of chemicals (see:

mem_somerville's picture

I think another issue that people outside of biology aren't aware of is that 90 days for a small animal is not the same as that of a human. Think about dog-years. And actually, while thinking about that--also consider that in fact research animals have been feed on GMO chow now for over a decade. That's many, many, many generations of these animals. If there was harm, animal technicians would know. These are the most studied animals on the planet.

Biotech Professor's picture

BT has been heavily used in organic farming. The effects of BT on human health are best known by those consuming organic foods (most of them do this for longer than 90 days). Although this is not a planned study or controlled data, it does give us some clues.