First, Vani Hari convinced Chick-fil-A to ditch the corn syrup. Then, she took Subway to task for including azodicarbonamide – "the yoga mat ingredient" – in their bread. Now, she's tackling everyone's favorite fall Starbucks order: the Pumpkin Spice Latte.

On Monday, Hari published a post on her popular blog The Food Babe titled "You’ll Never Guess What’s In A Starbucks Pumpkin Spice Latte (Hint: You Won’t Be Happy)." While Hari details the difficulty to finding an exact list of ingredients for the Pumpkin Spice Latte and other Starbucks drinks, the ingredients she does find are disappointing. The sweet beverage contains Caramel Color Level IV, artificial flavors, preservatives and a lot of sugar. The one thing that isn't in the Pumpkin Spice Latte is pumpkin.

Hari ends the post with a call to action for her readers to contact Starbucks demanding the coffee chain remove additives, sign a petition asking for organic milk at Starbucks and to share the blog post so others can put pressure on the coffee chain to make changes. The post has already racked up more than 346,000 Facebook likes and 580 comments.

Hari has been blogging about Starbucks since 2012, with a special focus on the caramel coloring that Starbucks uses in its Frappuccinos and a number of other products. While the use of caramel coloring is currently approved by the FDA, Hari believes that caramel coloring is "one of the most hazardous chemicals being added to our food." Studies have found that the additive increases risk of certain types of cancer in mice and the International Agency for Research on Cancer classifies byproduct 4-Mel as "possibly carcinogenic to humans."

Related: Subway to Remove Chemical From Sandwich Bread Following Blogger's Protest

Earlier this year, Hari says she had hoped to convince Starbucks to cut caramel coloring from their products without the media -- and social media -- blitz that typically follows one of her posts condemning a restaurant chain. At one point, in March, it looked like there would be an opportunity for Hari to visit the headquarters and speak about changes Starbucks could make. In May, Hari says that Starbucks slammed the door to collaborative change.

"I think if they had followed through with the initial invite, I wouldn't have been motivated to write this piece," says Hari. "I'm not looking to become a consultant for them... It was purely, let's have a discussion."

Starbucks spokesperson Linda Mills said that the coffee chain has maintained an "open dialogue" with Hari. However, Hari felt her attempts to create change at Starbucks behind the scenes were not producing any true results. And, if past experiences are any indication, when Hari wants a restaurant to make changes, she will do whatever it takes to make it happen.

There's no way that Starbucks is going to pull the Pumpkin Spice Latte off the menu. So, what does Hari actually want to change?

"First and foremost, they should respond by posting all ingredients online so the menu offerings are transparent to consumers," Hari says. "Secondly, they should remove all caramel coloring level IV from their espresso and coffee beverages immediately. Starbucks should offer organic milk at their stores would send a huge message to consumers that they care about using the best and most nutritious ingredients."

Starbucks' responses so far have been fairly limited.

Related: 'Tis the Season? Starbucks' Pumpkin Spice Latte Arrives Early This Year.

"We are actively looking at phasing [caramel coloring] out over time," says Mills. However, the coffee chain does not have any set timeline or immediate plans to get rid of the ingredient.

"If they are really making this commitment, they need to provide a timeline to their customers and the public," says Hari. "Millions of people continue to drink Starbucks flavored coffee drinks laced with this substance and could be harming themselves."

Starbucks is also considering listing at least the core ingredients of beverages online, something it had so far resisted, reportedly due to the variety of customization options. However, the chain is not looking to removing other chemicals or switching to organic milk, as Hari wishes they would.

Cutting caramel coloring -- a purely aesthetic ingredient -- and listing ingredients online seem like simple fixes if Starbucks wants to appeal to health-conscious customers and dodge negative PR. Hari has been able to convince big chains to make system-wide changes in the past by isolating one or two ingredients, such as the "yoga mat chemical" or corn syrup, that she feels are especially dangerous for customers and would be feasible for the company to cut. Caramel coloring has the potential to be another ingredient on the kill list.

"Why are they adding a possible cancerous ingredient to color coffee more brown anyways?" asks Hari. "In many instances you can’t even see the drink in the classic solid white cup they use."

Hari is convinced that if Starbucks doesn't start making changes fast, the sales of the iconic beverage will suffer.

"I’ve already heard from countless readers they will be giving up Starbucks Pumpkin Spice Latte for good because of the information I uncovered," she says.

Earlier this year, Subway announced only one day after Hari posted a petition to stop the sandwich chain from using azodicarbonamide that it would remove the chemical from its breads. Let's see if Hari can get Starbucks to find and implement an alternative to caramel coloring just as quickly. 

Related: How This Food Blogger Convinced Chick-fil-A to Go Antibiotics Free