Outlined below are the foods you should not put in your worm farm - some are bad for the worms’ stomachs, or they may just avoid them leaving them to rot, which may cause smells.
Dairy - yoghurt, cheese, milks
Bread, rice, pasta, processed foods - you can add the odd crust or bits of cooked rice off the dinner plate, but don't add lots of starchy foods. Worms don't like them and they may go off or attract pests.
Animal products - bones, meat, fish, shellfish
Acidic foods - citrus, pineapple, garlic and onions.
Spicy foods - worms are plain eaters, and don’t like spicy food such as chillies, chives, curries etc.
Oils - won't be processed by the worms so may cause smells or an unfriendly environment
Chemicals - avoid any materials contaminated with toxic chemicals, such as sawdust from treated wood, paper towel used with cleaning sprays, disinfectant wipes etc.
Worms love coffee grounds but mix them with other foods and paper. Large amounts can emit ammonium, so if you have a big quantities allow it to dry out and age first.
The same advice applies if you want to add chicken manure – it is high in nitrogen and needs to age first to blow off the excess ammonium.