Lunch meat,is one of the alternative names for cold cuts which are precooked or cured meat, sausages or meat loaves. These meats are often sliced and served cold in sandwiches or as delicacies. They are often purchased in vacuum packs in grocery stores or fresh from delicatessen or deli counters.
They are very popular around the world and are eaten in many cultures.
Unfortunately, guinea pigs are unable to eat any kind of meats at all, and that includes lunch meat.
They are strictly herbivores and so only eat raw vegetables so steer clear of any kind of meats when feeding your guinea pigs.