La nuova puntata vede l’ennesimo articolo terrorifico su tutti i tipi di OGM oggi commercializzati. Il testo sembra assai preoccupante, ma stranamente gli autori non chiedono che siano messi al bando i prodotti da agricoltura biologica che usano il Bt come pesticida. Strano, se ne saranno scordati.
Ovviamente non ci sono analisi comparate con altri prodotti simili e non si immagina nemmeno di mettere alla prova nelle stesse condizioni composti ritenuti sicuri. Gli sperimentatori non sembrano ricordare che la digestione degrada gli alimenti e già alcuni forum fanno i conti che i dosaggi per avere gli effetti desiderati sono insensati:
-I did some quick math on the Bt levels, and they only observed an effect at 100 ppm of Cry1Ab. Well, the levels of Cry1Ab in corn grain is 0.83 ppm, which means that to get high enough concentrations of Bt in your body, if you weigh 200 lbs, would be 200 / 0.83 * 100 = 24,000 lbs of grain!
Funny note - the reference they used for levels of Bt in corn said that there’s 0.83 +/- 0.15 ppm of Bt in the grain. But Seralini and company reported 1-20 ppm. The levels only get that high in the LEAVES for a brief period of time.
-Nobody eats raw field corn. Bt is denatured by heating and is inactive in this form. It is then digested. Bt is not absorbed into the bloodstream,
Very few GM critics seem to pay attention to Paracelsus’ observation that the dose makes the makes the poison but fewer still respect the basic paradigm of toxicology abbreviated as ADME (absorption, distribution, metabolism, and excretion).
Séralini has ignored the dose by exposing at much higher concentrations than would be expected to be encountered in real life. This is, however, normal for toxicological evaluation. Higher than expected doses are evaluated so that a safety margin (tolerable intake, acceptable daily intake, etc) can be determined. Thus our friend Séralini could defend himself against this charge.
The real crime in the experiment is an inappropriate route of exposure (directly on cells) which would not occur in the real world and the use of an irrelevant form (eg. not denatured). A good many chemicals and proteins that we consume would be toxic if applied directly to cells. If you don’t study a substance using the anticipated route of exposure the results are no meaningful.
As a side-bar I have to throw into the discussion that virtually no field corn is eaten by humans. In this country about 1-2% goes into Fritos, Doritos, tortilas, etc. In many of these products the corm meal is nixtalized which would destroy Bt. Thermal processing such as frying would denature the Bt anyway. Thus the anticipated human exposure to Bt is nil. One has to wonder why countries that import US maize for use as animal feed demand absolute safety when none of it is likely to enter the human food chain. Is anybody really thinking about what I have said in this paragraph or are they all brain dead?
Comunque l’articolo esce in tempo per giustificare la moratoria elettorale francese.