The only real process that works is a different person taking the money - our butchers wearing plastic gloves, put meat on a plastic sheet, may need to use two hands to cut sausaages off a string at which point the glove they will directly be taking the change with touches the meat - would you complain ? your changes has then been contaminated by the meat (but was probably already dirty) using credit card avoids him having to touch change for your transaction - need a butchers which does not do cash ?
I think you have to mince your own if you want tartare or rareish beefburgers