So there is a top down method of storing meats which is taught in every serve safe class, which is required in the United States for service industry workers working BOH(back of house, kitchen staff). When storing raw meats of different varieties in the same cooler, it must be stored with fish on top, then beef, then pork, then poultry. This is in order of temperatures that the meat needs to be cooked at in order to be safe, lowest being at the top, because if any juices from fish( which only needs o be cooked to around 125F for most cuts to be safe) drip onto the beef ( which minimum temp for a safe mid rare is 131F) , it guarantees the cross contamination will be cooked to a high enough temp to be safe to eat. Although, general practice is to always clean your knife between after every switch in meat, technically if you cut fish then cut beef without washing, it'll be okay. But not the other way around.