Introduction
Genetically modified organisms (GMOs) can be defined as organisms in which the DNA has been altered to involve some individual genes from another organism to carry a specific purpose.GM foods have some advantages both for the producer and consumer of these foods. GM crops are made mainly to have resistance against plant diseases caused by insects or viruses. Insect resistance is achieved by incorporating the toxin gene from the bacterium Bacillus Thuringiensis (BT). GM crops that permanently produce this toxin have been proven to require less insecticide. Virus resistance is achieved through introducing the plant to a gene from certain viruses to the extent that it becomes resistant to that virus. (Varzakas et. al., 335)
GM food has no greater risk than conventional food because transgenic Bt crops are environmentally less damaging than chemical insecticides, which is currently widely used to treat insects in conventional crops. GM corn is genetically altered to naturally express a protein from the bacteria Bacillus thuringiensis called the Cry protein, or delta endotoxins (Bessin 2001). This protein is toxic selectively to some insects, such as the European corn worm. A study by Sears et al. (2001) compared survival and growth rate of monarchs in a field of Bt corn expressing Bt 11 endotoxin to that of monarchs in a non-Bt, insecticide-treated area. Results show that survival of larvae in the insecticide-treated area was low (0-10%) and survival of larvae exposed to leaves of Bt corn was high (80%-93%). This supports the claim that insecticide is far more damaging for the environment compared to the toxin in Bt crops. Therefore, GM food poses no greater risk than conventional food, even less (Yang & Chen, 2015).
In addition to be safer than chemical insecticides, Bt crops also help reduce the use of insecticides. Naturally carrying Cry protein in its genes, Bt crops is insect-resistant and kills pests that previously had to be killed by using harmful insecticides. A research in China by Jia and Peng (2002) proved that population density of cotton pests was 443 to 1646 times lower in Bt-cotton plants than that in conventional plants, and the percentage of amage caused by pests in Bt-cotton was less than 1%, while damage of non-Bt cotton plants was up to 4090%. This confirms that Bt crops is more invulnerable to insects. As a result, growing Bt crops allows farmers to reduce the use of insecticide. Sanchis (2011) confirms this by claiming that Bt corn and Bt cotton have allowed consistent reductions in insecticide use, thereby reducing the environmental impact associated with insecticide use.
Besides reducing the use of chemical insecticides, GM crops are also environmentally friendly because it preserves biodiversity by only harming target insects. Delta endotoxins are very selective, generally not harming insects in other orders such as beetles, flies, bees and wasps. The process of making Bt strains are currently improved by involving new isolated strains that has higher insecticidal activity against targeted insect pests (Sanchis 2011). For example, a small biotechnology firm Ecogen constructed strain EG2424 that contains two plasmids, one is particularly active against European corn borer Ostrinia nubilalis and the second encoding a protein toxic to Colorado potato beetle Leptinotarsa decemlineata (Sanchis 2011). Bt-based ingredients are also considered safer for mammals, birds, and non-target insects than conventional insecticides (Sanchis 2011). The research by Jia and Peng (2002) also confirms that Bt protein is highly selective as Bt-cotton has significantly higher diversity of non-target insects compared to non-Bt cotton regularly sprayed by insecticide.
As Bt-endotoxin doesn’t harm non-target insects, GM corn also doesn’t harm mammals and humans. Hammond et al. (2004) held a study of feeding rats with grain from Roundup Ready corn, one type of GM corn, for 13 consecutive weeks where this corn supplies 33% of the rodent’s diet. When compared to rats that are fed with non-transgenic grain with the same nutrition levels, there are no differences in various parameters measured including weight gain, feed intake and efficiency, and other health quality measures. A high dose of 572 mg/kg CP4 EPSPS protein carried by Bt-corn is exposed to the mice in the experiment, while potential adult human exposure to that protein, assuming that no CP4 ESPS protein is lost during the processing of corn into human food, is at most 0.00027 mg/kg (Hammond et al., 2004). Swine, which are considered good models to study the safety of foods for human since they have similar digestive and cardiovascular system to human’s, were also given Roundup Ready corn grain at diet levels 68% and 82%. Likewise, they showed comparable health performance to the control group who was given non-transgenic corn. Therefore, it can be confirmed that GM corn, represented by Roundup Ready corn, is safe for human consumption.