These effects occur even though irradiated food is not itself radioactive. Gamma radiation depletes or destroys vitamins A, B, C, E and K and essential amino acids cysteine, methionine, histidine and tryptophan as well as enzymes. Enzymes are required for nutrient absorption and survival. No component of food remains chemically unchanged when irradiated. And the spores that cause botulism are not killed by irradiation - but their natural enemies are.
Irradiation is also environmentally dangerous.
Approval of food irradiation will cause the proliferation of facilities that will ship and use cobalt 60 and cesium 137, the principal radioactive elements used in food irradiation. Foods are being engineered for profit without adequate consideration of possible health effects. Nutritional value is inversely proportional to genetic engineering - more engineering, less nutritional value. Insects communicate with plants on a frequency that we can't hear, learning which ones are sick. Further, over 500 species of insects have become pesticide-resistant.