With their 6-year-old son already hospitalized with E. coli-related complications, a Brookfield couple wonders if their 3-year-old daughter might also be among those sickened in a nationwide outbreak of the bacteria linked to tainted spinach.

Anne Grintjes said that her daughter is now complaining of stomach cramps, a symptom her son had before being hospitalized with hemolytic uremic syndrome. The syndrome is a potentially fatal E. coli complication that can lead to serious kidney damage.

On Friday, California-based Natural Selection Foods voluntarily recalled its pre-packaged spinach and salad mixes containing spinach. Federal officials said that although they have not isolated any E. coli bacteria from spinach packed by the company, many patients have reported eating the company’s products.

Bill Marler of the Seattle-based law firm Marler Clark said that his firm will update suits filed against Dole Food Co. in Wisconsin and Oregon to include Natural Selection Foods.

Among Marler’s clients are Anna and Paul Zientek, a Milwaukee couple whose 6-year-old son and 3-year-old daughter developed E. coli-related syndrome after eating salads made from a package of Dole baby spinach they purchased on Aug. 25. Although the 6-year-old boy was released from Children’s Hospital of Wisconsin in Wauwatosa on Thursday, his sister remains hospitalized.