In May 2009, Nutro issued a recall of selected dry cat food due to excess levels of zinc and low levels of potassium, which the company blamed on a production error by a premix company. Nutro stated that it received no complaints related to the recall. Symptoms includes "reduction in appetite, refusal of food, weight loss, vomiting or diarrhea." Both consumeraffairs.com and PFPSA have claimed a link between this incident and earlier complaints and also questioned Nutro's claim of quality control and product testing. In June, lab tests of a sample of "Nutro Max Cat Adult Roasted Chicken Flavor" showed zinc levels at 2100 ppm. Dr. Stephen Hansen, a veterinary toxicologist and senior vice-president of Animal Health for the American Society for the Prevention of Cruelty to Animals (ASPCA) described the zinc levels as "awfully high". While he stated that the long-term effects of such levels are not known, he mentioned the possibility of "significant intestinal upset and liver and kidney damage." Unlike the 1000 ppm maximum for dog food, the cat food maximum set by AAFCO is 2000 ppm. In comparison, the European Union's maximum for all animal feed is 250 ppm, with a recommended maximum of 150 ppm.