"This is the craziest thing I've ever seen ... and people eating this," she said in videos posted on social media.
"As I go back and I look ... these people are literally killing frogs ... bullfrogs. Aren’t those poisonous? Aren’t those the ones that give you warts and boils and stuff?"
The 29-year-old later apologised following a backlash.
"I just wanted to come on here and apologise sincerely from the bottom of my heart," she wrote on social media.
"I understand that I am so privileged as a professional athlete to be able to travel all around the world and experience cultural differences, which is one of the things I love so much about what I do.
"I have had nothing but the most amazing experience and time here and in the tournament. Everyone has been so kind and so gracious and the things that I said are not representative of that at all."
Townsend, who was involved in a heated confrontation with Jelena Ostapenko at the US Open last month, is part of the US team which will take on Kazakhstan in the quarter-finals of the team tournament in Shenzhen.