 In the following weeks, several other companies who received the contaminated wheat gluten also voluntarily recalled dozens of pet food brands.One month after the initial recall, contaminated rice protein from a different source in China was also identified as being associated with kidney failure in pets in the United States, while contaminated corn gluten was associated with kidney failure with pets in South Africa.As a result of investigating the 2007 pet food recalls, a broader Chinese protein export contamination investigation unfolded, raising concerns about the safety of the human food supply.