"We’ve got to have a safe and assured supply," he said.
"We serve 68 million customers a day and can’t afford to have one person go to McDonald's and come away with a food borne illness.
"It goes straight to the media and with the electronic age the way it is, tweeting and tweeting, it gets out there pretty quick.
"It’s rapid. It’s instantaneous."
Mr Southworth outlined the fast-food giant’s plans for growth during the next two years at the Australian Meat Industry Council business conference earlier this month in Adelaide.
McDonald's plans to open 3100 restaurants in the Asia/Middle East/Africa region by 2014, including 1050 in China, 540 in Japan, and 110 in Australia.
It opened 1000 restaurants globally in 2011 and spent $3.8 billion on beef.
"We’re continuing to grow," Mr Southworth said.
"And our supply chain has to feed this growth.
"Traditionally, priority meat was going to the United States but increasingly we’ve got proportionately more going into that APMEA (Asia Pacific, Middle East and Africa) zone."
Australian and New Zealand meat is supplied to McDonald's through the McDonald's Asia Pacific Consortium (MAC) which is owned by five North American McDonald’s beef pattie manufacturers and based in Australia.
MAC supplies meat to all of Australia and NZ McDonald's restaurants and supplies 15pc of US demand. It processed and purchased 110,000 tonnes of beef last year - or 12pc of the 900,000t consumed by McDonald’s.
Managing director Frank Carbone says Australia and NZ are a key strategic source of beef for McDonald's in the Pacific and APMEA region.
"That will continue to grow in relevance as these markets continue to grow," he said.
"There is growing demand for product over this part of the world.
"Other beef supply countries are having their issues at the moment and we seeing that demand come through the McDonald's system as well.
Mr Carbone said Asian market was "mind boggling" in its size, with a new McDonald's store opening "somewhere in China every 36 hours".
"And while beef doesn’t represent a huge base in those restaurants, it continues to grow in its profile and presence.
"Some of our focus will be to work more closely and strategically with our processing community, to see if we can drive a bit more shared value in that supply chain."