"Potatoes, thank goodness! That's a good start," former Mythbusters host Grant Imahara says as he goes on to reveal the 13 other ingredients contained in the US version of the McDonald's fry.

The TV personality traveled to the fast food chain's potato processing plant in Idaho to see the production process from start to finish.

During his investigation he found that there are two rounds of frying.

He also discovered that dimethylpolysiloxane - a form of silicone found in Silly Putty - is used in the making of McDonald's fries along with a petrol-based chemical called tertiary butylhydroquinone (TBHQ).


However, he reassures viewers that these are both safe additives used for perfectly good reasons.

Note: The formulation used in the US differs to the one used in New Zealand. In New Zealand it only contains potato, 0.02% of dextrose and the canola oil they are cooked in, said Kenny Simon, Head of Communication at McDonald's Restaurants NZ.

Dimethylpolysiloxane, which Imahara struggles to pronounce, is added for safety reasons to prevent cooking oil from foaming.

While tertiary butylhydroquinone (TBHQ) is applied as a food preservative.

Imahara explains that there are numerous steps involved in the creation of McDonald's fries.

First potatoes are harvested from fields before being peeled, cut and blanched.

They're then fired through a cutter at up to 70 miles an hour into thin sticks.

After being chiseled into the perfect shape, the strips of potato are sauced with a blend of canola oil, soybean oil, hydrongenated soybean oil, natural beef flavor, hydrolyzed wheat, hydrolyzed milk, citric acid and dimethylpolysiloxane.


Dextrose - a natural sugar - is sprayed on the batons to help them maintain a golden fried color.

Sodium acid pyrophosphate is also added to prevent the fries from going grey.

Last but not least, salt is sprinkled on for flavor.

The fries are then flash frozen at the Simplot factory and transported to McDonald's outlets across the country.

Once they are at restaurants, the potato sticks are fried for a second time.

The oil blend is similar to the factory mix, with the addition of tertiary butylhydroquinone and hydrogenated soybean oil - a manufactured form of trans fat.


And voila! McDonald's World Famous Fries are served.

A large serving of the finished product contains 510 calories, 6gms of protein, 24gms of fat, 67gms of carbs and 290mgms of sodium.

The recipe for McDonald's French Fries differs greatly in the UK where it does not include the Hydrogenated Soybean Oil, Canola Oil and, notably, the Dimethylpolysiloxane, according to a study by 100daysofrealfood.com.

McDonald's digital series Our Food. Your Questions comes as the company fights to boost its performance in the US, where sales slid at established locations in the last quarter of 2014.

In addition to increased competition, McDonald's is trying to keep up with changing tastes, with places such as Chipotle marketing their food as more wholesome alternatives.

To improve the image of its food, McDonald's recently rolled out chicken wraps with sliced cucumbers and the option to substitute egg whites in breakfast sandwiches.


It also plans to eventually let people swap out the French fries in value meals with options like salad or vegetables.

McDonald's answers questions about fries

Do you use real potatoes for your fries?

Yep. The most common ones we use include the Russet Burbank, Ranger Russet, Umatilla Russet and the Shepody - varieties known for producing a flavorful fry that's crispy on the outside and fluffy on the inside.

How do you make your fries?

The potatoes we use for our World Famous Fries are made from varieties including Russet Burbank, Ranger Russet, Umatilla Russet and the Shepody.

The suppliers we work with first peel, cut and blanch the potatoes. They then dry, partially fry and flash freeze the fries for our restaurants. Once in our kitchens, we cook them in our Canola blend oil so you can have them crispy and hot - just the way you like them.


Do you add any type of flavor when preparing your fries?

Yes. When our suppliers partially fry our cut potatoes, they use an oil blend that contains beef flavoring. This ensures the great-tasting and recognisable flavor we all love about our World Famous Fries. The fries are finally seasoned with salt after they're cooked in our kitchens and served hot to you.

What kind of oil do you use to cook your fries?

We use an oil blend made from four different kinds of oils: canola, corn, soybean and hydrogenated soybean. This ensures the savory flavor and crispy texture of the World Famous Fries you love so much.

How much salt do you add to your fries?

We add a small amount of salt to our fries after we've cooked them in our kitchen.


Can I order fries without added salt?

Sure. You can still enjoy the great taste of our World Famous Fries without salt.

Just ask for no salt when placing your order and we'll be happy to prepare a batch for you. Please understand it's possible a small amount of salt may be transferred from the bin or the scoop.

Are your fries vegetarian friendly?

At this time, none of our menu items are certified as vegetarian or vegan. The oil our suppliers use to partially fry our World Famous Fries has a natural beef flavoring, which also contains hydrolyzed milk as a starting ingredient, added to enhance the taste.

It's important to note that, despite taking precautions, normal kitchen operations may involve some shared cooking and preparation equipment, areas and utensils, and there is a possibility for your food items to come in contact with other food products.


Are the fries at McDonald's gluten-free?

Currently, we don't offer a gluten-free menu.

The oil our suppliers use to partially fry our fries has a small amount of flavoring that uses hydrolyzed wheat as one of its starting ingredients. We also want you to know that despite taking precautions, normal kitchen operations could involve some shared cooking and preparation areas, equipment and/or utensils.

Bottom line: we know all of our customers may have different needs. So, talk to your health care provider for possible meal options.

How would you recommend reheating your fries once they're cold?

Our World Famous Fries are best enjoyed when they're served fresh and hot. For that reason, we don't recommend any specific reheating method.


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