Molds don't feed off plastic itself, it's more of just growing on it. Fungi need something organic to feed off, so it could be plastic additives used in manufacturing, stray skin cells or skin oil from the factory workers, bacterial growth or contact with dirty water at some point of manufacturing.
The trouble breathing could be an example of post hoc bias, but may also be due to an increased concentration of fungal spores inside the packaging. Molds prefer dark, damp places and the inside of a cardboard box is exactly that, especially if they've been shipped by sea. IIRC, about 6% of the general population displays hypersensitivity to fungal spores, and even those who aren't allergic can display symptoms if the concentration of spores is high enough. Exposure also exacerbates existing respiratory illness like asthma or COPD.
White and fluffy growths aren't specific at the size the growths on the plastic are so the only way to get a species identification is by sending a sample to a lab for microscopy and culture.
I don't know enough about materials to guess the effects of various disinfectants on the plastics, paints and pins/screws.
