Premium beverage company Bolthouse Farms is recalling approximately 3.8 million bottles of protein shakes because the products may be spoiled—causing the beverages to appear lumpy, taste unpleasant and have an off odor.

The California-based company—which is a leading carrot distributor in in addition to producing its smoothies, shakes, juices and dressings—says the problem was identified after the company received consumer complaints about the products, including reports of illness. The exact cause of the problem is currently under investigation.

Products affected by the recall include multiple varieties of Protein PLUS shakes with best by dates between June 20 and Sept. 18 as well as select Mocha Cappuccino Perfectly Protein products. The company says approximately 3.8 million bottles were distributed nationally and another 277,000 were distributed in Canada.