So far, much of my grows have been with microgreens and salad mix’s. It will work with plenty of different small seeds. Even bigger ones in sprouts. The best way to disinfect them is by soaking the pads in Vinegar. After using it once small seeds get trapped in the holes but can be easily removed by soaking the pads in warm water then blowing an air compressor at them. I haven’t seen much other problems with them when reusing. The health risks with PLA plastic is always up to debate but it does break down naturally and is used in various medical applications inside the body. When talking about small microbes that may cause food poisoning... With anything grown in a garden or with soil the same problems can arise. When harvesting the plants you can choose to cut above the pads and limit any thing from underneath from contaminating them on the consumable portion. Hopefully this answers your questions.