Myths surrounding pig fat in McDonald's milkshakes and whether those 100 per cent beef patties really are all beef are set to be answered with a new "Our Food, Your Questions" campaign.

The New Zealand and Australian versions of the campaign follow a successful Canadian version launched last year in which thousands of questions about the quality of ingredients and inclusion of additives and chemicals were answered.

Questions included: "Dating back to at least 1978, the rumour claims that McDonald's restaurants use earthworms in their hamburgers, is this statement true?".

The answer: "Absolutely not. This is a myth. Our hamburger patties are made with 100 per cent pure Canadian beef, with no fillers, binders, or additives."

No questions have yet been answered on the New Zealand "Our Food, Your Questions" site, as a team of moderators and McDonald's marketing staff work their way through the 180 questions currently submitted.

McDonald's New Zealand managing director Patrick Wilson said the initiative was an effort to put customers' minds at ease over what went into their products.

One question was whether their food was cooked in trans fat, he said. "And obviously the answer is 'no'."

Some questions would be relatively easy to answer, while other would require further research and could take a couple of days to answer, Mr Wilson said.

The company was prompted to create the site so people could ask their questions in a "transparent and very engaging way", he said.

"This is about for us, providing those answers, but also providing an opportunity to dispel a lot of myths around our food.

"We're proud of our food, we've got nothing to hide and the opportunity to engage in a genuine way, more on a one-on-one basis with customers, why wouldn't you take that opportunity?"

The University of Auckland senior marketing lecturer Dr Mike Lee said the clever PR campaign was probably aimed at appeasing consumer watchdogs and critics of the company.

"Given that it's the biggest fast food brand, they're often the first target as well, it's not saying that their stuff than is any unhealthier than the local fish and chip shop, but they do steal the limelight in that sense.

"They kind of have to respond to negative perceptions of the industry a little bit more proactively.

"The other thing they have going against them is being a huge multinational, there is suspicion of 'where are you getting your products from' and 'how much are you supporting the local economy'."

While the campaign was great for current McDonald's customers, it was unlikely to convert those who avoided the franchise, Dr Lee said.

"With any of these PR stunts, they're often preaching to the converted."

However, addressing myths and critics head-on was one of the best ways to quell rumours and negative social media, he said.

Other questions asked overseas:

Cassandra D asked: "How many times do you change your oil?"

The answer: "We change the oil in our fryers on a weekly basis".

Jani S asked: "When you say 100 per cent beef, do you mean the whole cow: the organs, snout, brain, kidneys etc etc, or just the plain beef we buy at the grocer?"

The answer: "We wouldn't call it plain beef, but it sure is beef. We only use meat cut from the shoulder, chuck, brisket, rib eye, loin and round."

John N asked: "Is your beef actually 100 per cent pure beef, or is that just the name of the company?"

The answer: "The reason we say our hamburger patties are 100 per cent pure beef is because that's exactly what they're made of: 100 per cent pure beef".

Meanwhile in Australia, one diner asked: "Do your milkshakes have pig fat in them?"

The answer: "Absolutely not. Our thickshakes get their signature thickness from our cooling and blending process as well as a few common thickeners that are in our dairy mix."

Claire J asked: "What percentage of your chicken nuggets are actual meat vs. muscle, tendon, cartridge, organs and carcass."

The answer: "Hi Claire, you'll be pleased to know the Chicken McNuggets are made with 100 per cent Australian chicken breast (which is muscle) with some skin. This makes up 95 per cent of the meat portion with the remaining 5 per cent of ingredients being water, salt and mineral salts, which help retain moisture in the meat for succulence."

Nazia B asked: "Are the chips coated in lard before they are frozen and packaged?".

The answer: "Not at all. Our French Fries are par-fried in canola oil before freezing by our suppliers."

Kyle C asked: "I've heard 'pink slime' is used as a preservative in your meat patties, is this true?"

The answer: "You may be surprised that it's a very short answer. No, we have never used 'pink slime' in any of our products."

- APNZ