Very basically, food-related biotechnology is the process by which a specific gene or group of genes with desirable traits are removed from the dna of one plant or animal cell and spliced into that of another. Such beneficial genes might come from animals, (friendly) bacteria, fish, insects, plants and even humans. In some instances, genes that create problems (such as the natural softening of a tomato) are simply removed and not replaced. Tomatoes, for example, are generally picked green and gas-ripened later because, during shipping, they would become soft, bruised and unmarketable. A bioengineered tomato, however, can be picked ripe and shipped without softening. The objective of food biotechnology is to develop insect- and disease-resistant, shipping- and shelf-stable foods with improved appearance, texture and flavor. Additionally, biotechnology advocates say that the process will produce plants that are resistant to adverse weather conditions such as drought and frost, thereby increasing food production in previously prohibitive climate and soil conditions. They also envision increasing nutrient levels and decreasing pesticide usage through biotechnology. On the other hand, critics argue that, because biotechnology is producing new foods not previously consumed by humans, the changes and potential risks relating to such things as toxins, allergens and reduced nutrients are unpredictable. They also worry that, because genetically altered foods are not required to be labeled, people with religious or lifestyle dietary restrictions might unintentionally consume prohibited foods. In answer to such concerns, the FDA has issued the following evaluation guidelines by which a bioengineered food will be judged for approval: 1. Has the concentration of a plant's naturally occurring toxicant increased? 2. Has an allergic element not commonly found in the plant been introduced? 3. Have the levels of important nutrients changed? 4. Have accepted, established scientific practices been followed? 5. What are the effects on the environment?