What group of arthropods can contribute to food-borne gastroenteritis outbreaks?

Flies and cockroaches are known vectors for food-borne pathogens and can significantly contribute to gastroenteritis outbreaks. These arthropods are often found in unsanitary conditions and are known to carry bacteria, viruses, and parasites on their bodies and in their feces. When they come into contact with food, they can contaminate it, leading to illness when ingested by humans. Flies, particularly houseflies, are notorious for landing on decaying organic matter and then transferring pathogens to food items. Cockroaches also thrive in dirty environments and can carry pathogens linked to gastrointestinal disease.

In contrast, the other groups mentioned do not have the same level of involvement in food contamination. Mosquitoes and ticks are primarily associated with the transmission of diseases through bites rather than food contamination. Worms, a type of parasite, can cause gastrointestinal issues but do not fall into the same arthropod category. Ants and spiders do not typically serve as vectors for food-borne pathogens in the same widespread manner as flies and cockroaches. Thus, the role of flies and cockroaches in food-borne gastroenteritis makes them the correct answer.