Question: what is the reason for irradiating food with gamma rays
[{'answer': 'sterilization of foods', 'provenance': [{'wikipedia_id': '15374', 'title': 'Food irradiation', 'start_paragraph_id': 1, 'start_character': 615, 'end_paragraph_id': 1, 'end_character': 637, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'delaying or eliminating sprouting or ripening'}, {'answer': 'to improve food safety by extending product shelf - life ( preservation )'}, {'answer': 'reducing the risk of foodborne illness'}, {'answer': 'as a means of controlling insects and invasive pests'}, {'provenance': [{'wikipedia_id': '15374', 'title': 'Food irradiation', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 874, 'bleu_score': 0.6428145459743511, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5303035714373848586}, 'section': 'Section::::Abstract.'}]}]