The FDA began investigating the reports of contamination immediately and received information from the companies who manufacture infant formula for the American market that they are not importing infant formula or source materials from China. The following manufacturers have met the necessary FDA requirements for marketing milk-based infant formulas in the United States: Abbott Nutritionals, Mead Johnson Nutritionals, Nestle USA, PBM Nutritionals, and Solus Products LLC. Also, one manufacturer, SHS/Nutricia, Liverpool, England, markets an amino acid based exempt infant formula that does not contain any milk-derived ingredients.