The produce grades used on Ample cover both human-grade and non-human grade food. We use Extra Class, Class 1 and Class 2 for human-grade food, based on the government's standard and general marketing standards (found here). We then have 2 grades for non-human consumable produce that can be sold as animal feed or go to anaerobic digestion to generate energy. These grades are called Feed Grade and AD (anaerobic digestion).
Please be aware that Feed Grade and AD are not suitable for human consumption.