I was thinking about how bees can produce honey and human can eat it. After that I came up with question. What are the smallest animal that can produce food for human?
It would depend on what you consider food, but if you consider things that contribute to food substances (e.g. food dyes) then cochineal scale mites are only about 5 mm (0.2 in) long and produce a red dye that is commonly used as a food colorant.
There are also several ant species of similar size that are eaten as food sources. For example, Liometopum apiculatum (6-7 mm adult) grubs are/were harvested as a food source in parts of the USA and Mexico.