The woman in the video on Friday announced on Twitter that "I lost my job for this."
The viral clip drew a stream of commentary and complaints on social media, with one Twitter user calling it "proof" that the company's mac and cheese "is garbage."
Others were disdainful that anyone would be surprised to learn that the restaurant chain used frozen food. "Did people really think there was a chef hanging out in the kitchen of Panera Bread making their mac and cheese? This is literally how every fast-food joint operates," declared another Twitter user.
"We can't comment on personnel matters," a spokesperson for Panera told CBS MoneyWatch.
According to Panera, it sells more than 3 million mac-and-cheese servings a month "Our mac and cheese is made off site with our proprietary recipe developed by our chefs and using our sourced ingredients that met our standards for our clean menu offerings," the spokesperson said. "It is shipped frozen to our baker cafes — this allows us to avoid using certain preservatives that do not meet our clean standards."
Privately held by JAB Holding, Panera operates more than 2,300 bakery-cafes in the U.S. and Canada.