Twitter users are salty over a new suggestion by a Harvard professor who says the correct serving size for french fries is only six. USA TODAY

Del Taco already is known for serving Crinkle Cut Fries along with tacos.

Now the fast-food chain with 580 restaurants in 14 states has cooked up two new fry-related creations – a lightly French fry-scented soap and Fresh Faves Box meals that include fries.

Unlike the Fresh Faves meals available in four varieties at locations nationwide, the limited-edition soap called “Eau