The food, meant for families affected by drought, was seized during a raid on an al-Shabaab training camp outside Mogadishu this week, Voice of American reported Friday.
Mission spokesperson Eloi Yao said the African Union forces recaptured the village of Lanta-Buro during the raid.
"Some of those places that are strategic to al-Shabaab are being captured," Yao said. "And Lanta-Buro is a major achievement because it was serving as a training ground to the enemy. ... It's a major blow."
The mission also recovered a cache of machine guns and bomb-making equipment during the raid.