News & Events

Genetically Modified Food and Canning

Author: Andrew Morgan Tennant (Lecturer, UCSI University)

Genetically modified (GM) foods are foods derived from organisms whose genetic material (DNA) has been modified in a way that does not occur naturally, e.g. through the introduction of a gene from a different organism. Currently available GM foods (GMF) stem mostly from plants (WHO, 2013).

So some of the questions that naturally come to mind are;is GMF safe to eat?,will canning a GMF have any adverse effects?, how do I tell if it is in any food I buy?, and is GMF in Malaysia? Let’s look at these questions one by one.

Firstly, is it safe to eat food made from, or derived from, genetically modified plants, animals, or micro-organisms?

Well the answer in short is, as far as has been seen so far, there have been no adverse human health effects reported that are attributable to GMF or products from genetically modified organisms. The introduced DNA or proteins that result from the introduced genes are made of the same components as the originals and they go into the body in the same way. That is, they are eaten and are broken down by the digestive process. However, because there are different ways that different genes can work in different organisms, each genetically modified organism (GMO) needs to be assessed individually. Despite this requirement to assess individually and having no broad one way covers all, there are relatively few issues where human health and food safety are concerned. In reality, this means that the only key issues with regards to human health and food safety are possible new allergens (proteins that react with the immune system of the body to cause an immune reaction or allergic reaction), possible toxic effects that any proteins produced by the genes that have been inserted may have on humans, and possible antibiotic resistance gene transfer to native microbial intestinal flora.

In terms of possible allergens, all current GM foods are required to be tested for known allergens before they gain approval to release to the consumer and, to this date, no allergens have been detected in foods that are currently in the market. In addition the World Health Organisation (WHO) provides oversight by regularly evaluating protocols for GM testing.

Note 1: The safety assessment tests required for GMF.
“The safety assessment of GM foods generally investigates: (a) direct health effects (toxicity), (b) tendencies to provoke allergic reaction (allergenicity); (c) specific components thought to have nutritional or toxic properties; (d) the stability of the inserted gene; (e) nutritional effects associated with genetic modification; and (f) any unintended effects which could result from the gene insertion” (WHO(a), 2013).

The toxic effects of certain gene products are also covered in regulatory testing (see Note 1). In addition, the gene products that are targeted to help the plant defend against insects and other pests are not usually toxic to humans. The most well-known example is probably the protein produced by the CRY gene of Bacillus thuringiensis, commonly known as Bt (See box 1 for testing requirements). Thedelta endotoxin protein productof the CRY gene is specific to lepidopteran larvae because it must be activated by certain physical conditions not commonly found in humans, higher animals and most insects.A number of crops have been engineered to express this toxin including "Bt corn", "Bt potato", "Bt cotton" and "Bt soybean". It should be noted that there are numerous studies that have shown that Bt GM crops have LESS exogenous toxin from some of the common fungi that can grow on the crops mentioned above. Of particular importance are mycotoxins. These toxins are produced by the invading fungi and have a number of adverse health effects on humans including gastrointestinal disorders, immune system dysfunction, and cancer.

Antibiotic resistance gene transfer has been a concern. However, currently there are no reported gene transfer cases and WHO actively encourages no use of these genes in GMO’s, or their products, that are intended for human consumption.

Box 1: Data required from EPA reassessment of Bt crops
For the reassessment, the EPA required companies/applicants to provide the following data:

For all Bt crops:
• Analytical methods for detecting Bt residues in commerce.
• Protein expression level data in various plant organs, (expressed in terms of dry weight for consistency among different PIPs).

• Protein levels in soil. • Field data regarding possible impacts on nontarget insects.
For Bt corn:
• Monarch butterfly studies evaluating fitness and reproductive costs from subchronic exposure to Bt corn.
• Chronic avian studies (e.g., poultry broiler feeding study).
• Insect resistance management data regarding (1) potential for north-to-south movement of Helicopverazea (a polyphagous pest known as the corn earworm when a pest of corn and as the cotton bollworm when a pest of cotton), as movement of H. zea exposed to Bt from the corn belt and their overwintering in cotton regions could affect resistance; (2) impact of conventional chemical insecticide use on the effectiveness of a refuge producing susceptible insects; and (3) development of discriminating concentration bioassay for Cry1f corn to help in monitoring for resistance in European corn borer, corn earworm and southwestern corn borer.
For Bt cotton:
• Insect resistance management data regarding (1) potential for north-to-south movement of cotton bollworm; (2) alternative plant hosts, to demonstrate whether they serve as an effective refuge in generating Bt susceptible insects; and (3) insect resistance management (IRM) value of sprays with different chemical insecticides used in conventional and Bt cotton.
For Cry1Ab corn and Cry1Ac cotton:
• Comparison of amino acid sequence to known toxins and allergens via stepwise 8-amino-acid analysis.
For MON810 Cry1Ab corn
• Processing and/or heat stability data.

The second key concern is whether canning will have any deleterious effects on the GMF. That is, will something happen to the GMF to make it unsafe?

The simple answer is that this is very unlikely, because the GMF has the same basic components as so called traditional foods and would be subjected to the same processes and quality control procedures. Because the GMF has already been assessed for any allergens and possible toxic effects before it is approved for release it is as likely to contain anything new as any other newly introduced traditional food. That is to say that this is very unlikely as well.

Thirdly, how do I tell if the food item has GMF? Is there any labelling requirement?
If there is no information supplied on the product label then for a canned product, or any product for that matter, there is no way to tell the difference between GMF and traditional types of food. Malaysia does have a set of regulations that have been amended to enforce GMO labelling. This set of regulations is:

Food Regulations 1985, amended in 2010 (Ministry of Health, MOH).
 Approval (regulation 3A)
 Labelling [ regulation 11(3A), 11(6), 11(7a-e)

It is important to note that these regulations will be enforced in July 2014 and that the product will not be labelled when GMO content is not more than 3% of the food ingredients, “provided that this presence is adventitious [i.e. by chance] or technically unavoidable.”
In addition there are a number of exemptions to this rule.

Exempted products include:
• Highly refined foods e.g. refined oil, plant sterol, boiled sweet, sugar, corn syrup, honey and dextrin (other than that with altered characteristics).

• When novel DNA and/or novel protein is not present in the final food:

  • Processing aids and food additives (e.g. dextrin).
  • Acidic foods (e.g. pickles and vinegar).
  • Salty foods (e.g. soy sauce).

• Food from animals fed with GM animal feed (e.g. meat, milk, eggs).

• Foods produced from fermentation using GMM (Genetically Modified Microorganisms) not present in the final products (e.g. vitamins, amino acid).

• Foods produced with GM enzyme (e.g. cheese, bakery products produced with amylase).
So, what this means is that there is currently no labelling requirements and that there are many exceptions.

Lastly, does Malaysia already have any GMF currently available for purchase in stores?
Well, given the labelling requirements currently in force and the fact that it is impossible to tell just by looking at a food whether it is GMF or not it is difficult to say. If farmers are using GM crops in Malaysia then almost certainly yes. Also, if any of the crops or material from those crops that come from the main GM crop growing countries (USA, Brazil, China) is being imported as part of food manufacturing then the answer is also that it is likely.

So what can we conclude from this?

We can conclude that so far there seem to be no adverse effects on human health resulting from GMF and that the assessment and regulatory procedures seem to be working, and that in some cases there may be a reduction of exogenous toxins resulting from using GM crops. We can also conclude that any canning process will have no effect on the health, toxicity, and nutrient properties of GMF. Lastly, we can say that when the GM labelling regulations come into force in Malaysia it is your choice (the consumer) about what you buy.

Mendelsohn, M., Kough, J., Vaituzis, Z., &Matthews, K., 2003. Are Bt crops safe? Nature Biotechnology, vol. 21, no.9

Singh, G., Tan, J.E., 2013. What Malaysians Should Know About GMOs, and GMO Labelling in Malaysia.

Tzotzos, G.T., Head, G.P., Hull, R., 2009. Genetically Modified Plants: Assessing Safety and Managing Risk. Academic Press.
WHO, 2013.Health topics: Food, Genetically modified.

WHO(a), 2013. Food safety.
Wu, F., 2012.Human Health Implications of GMOs: A Focus on Bt Maize and Mycotoxin Reduction. International workshop on socio-economic impacts of genetically modified crops co-organised by JRC-IPTS and FAO Workshop proceedings. Publications Office of the European Union, Luxembourg, Scientific and Technical Research series- ISSN 1831-9424.