Genetically Modified Organisms - Feeds and the Food Chain

Dr. Maurice Eastridge, Extension Dairy Specialist, The Ohio State University

Biotechnology is part of our everyday lives, whether in the medical community or food industry. However, the word "biotechnology" gives rise to anxiety for some people because it is associated with unnatural changes that lead to unknown implications. Genetically modified organisms (GMO) result from the application of in vitro nucleic acid techniques (e.g. rDNA) or fusion of cells to overcome the natural physiological reproductive or recombination barriers and that are not traditional techniques for breeding and selection (FAO and Food Nutrition Paper, 2004). In other words, they result from the change in genetic makeup other than by traditional breeding and selective practices to achieve desirable characteristics. It is important to understand the benefits of biotechnology and how people and the environment are protected from potential adverse effects of GMO.

Risks associated with GMO on human health and the ecology are the primary foci for evaluating their potential use. With respect to human health, allergenicity (response to certain proteins), potential toxicity, and simultaneous effects on more than one characteristic of an organism are evaluated. From the ecological perspective, potential effects on nontarget species, effects of gene flow (from one organism to another), and evolution of resistance (e.g. pest resistance to pest-protected plants) are assessed.

Many years of research are conducted in laboratories before a potential GMO can be considered for public use. During this research, the risks described previously must be reviewed and the total implications to the food chain assessed. For example, a new GMO corn could directly enter the food chain or be fed to animals which results in the need to assess the effects of the GMO on the animals and the animal products that enter the food chain (Figure 1). The regulatory authority for GMO lies with the United States Department of Agriculture (USDA), Food and Drug Association (FDA) , and the Environmental Protection Agency (EPA) (Table 1). These agencies have joined together for working with GMO; see the United States Regulatory Agencies Unified Biotechnology web site: These agencies have developed a "US Database of Completed Regulatory Agency Reviews" that can be found at: These reviews establish approval for the three following categories of use:

  • "Food" use means that a product has completed an FDA review for consumption by humans, and if the product is a plant that contains a plant-incorporated protectant (PIP), the PIP has completed EPA reviews (cPIP),
  • "Feed" use means that a product has completed an FDA review for consumption by animals and cPIP; and
  • "Planting" use means that a product has completed USDA-APHIS review for cultivation in the United States and cPIP.

Figure 1. Relationship between research, new plant developments, feedstuffs for animals, and the food chain.

Table 1. Regulatory authority for genetically modified organisms.1

USDA (safe to grow) Plant pests, plants, veterinary biologics Federal Plant Pest Act
FDA (safe to eat) Food, feed, food additives, veterinary drugs, human drugs, medical devices Federal Food, Drug, and Cosmetic Act (FFDCA)
EPA (safe for the environment) Microbial and plant pesticides, new uses of existing pesticides, novel microorganisms Federal Insecticide, Fungicide, and Rodenticide, Act; FFDCA; Toxic Substances Control Act

1Taken from NRC, 2000.

Some GMO may fall into the category of Generally Regarded As Safe (GRAS), whereby a company has to file a request to FDA for the said GMO to be acknowledged as a GRAS and the burden falls to FDA to identify why the item should not be accepted as GRAS. A list of substances for which GRAS status has been requested and FDA's action is located at: The GRAS process relays somewhat on the principle of "substantial equivalence", which embodies the idea that existing organisms used as food, or as a source of food, can be used as the basis for comparison when assessing the safety of human consumption of a food or food component that has been modified or is new (Genetically Modified Crops: Assessing Safety, 2002).

Some examples of GMO in crops are:

  • Glyphosate (Round-up®) tolerance for soybeans, canola, corn, beets, alfalfa, and cotton {herbicide resistance},
  • YieldGard® (Monsanto, St. Louis, MO) for corn {insect resistance; corn borer; protein from Bacillus thuringiensis (Bt)},
  • Bollgard® (Monsanto, St. Louis, MO) for cotton (Bt; genetic resistance to tobacco budworm, pink bollworm, and cotton bollworm}, and
  • Hopperguard® (Land O' Lakes, St. Paul, MN) for alfalfa {genetic resistance to potato leafhoppers}.

These crops can also be fed to animals that then provide foods for human consumption. An example of direct GMO use in the dairy industry is in the use of bovine somatotropin (bST; Posilac®, Monsanto, St. Louis, MO. A plasmid from Escherichia coli is removed, the bovine gene for somatotropin (growth hormone) is inserted into the plasmid, and the plasmid in reintroduced back into the E. coli. The bacteria then are grown in a fermentation system, and afterwards, the bST produced by the bacteria is separated, purified, mixed with a carrier, and dispensed into single use syringes. This bST was introduced in February, 1994 and today, Monsanto is selling the product to about 13,000 dairy producers among the 50 US states (

The US has among the most efficient food production system and the most safe food supply. It will continue to be a high priority to provide for safety of the food supply for humans and animals and to protect the environment, whether it be from influences from GMO or otherwise. Research must continue to provide the scientific foundation for addressing the risks and benefits of biotechnology.


  • Genetically Modified Crops: Assessing safety. K.T. Atherton, ed. Taylor and Farncis, New York.
  • National Research Council. 2000. Genetically Modified Pest-Protected Plants. Science and regulation. Natl. Acad. Press, Washington, DC.
  • Safety Assessment of Foods Derived from Genetically Modified Animals, Including Fish. 2004. FAO and Food Nutrition Paper 79, Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO).