Tainted dog food - could it have caused his death & ketones in his urine?

Our Germand Shepherd suddenly became lethargic, with no appetite, but an unquenchable thirst, and began having HUGE urine accidents indoors (never happened before.) Eventually, he just layed down and did not want to get up. We took him to vet, and a quick urinalysis detected keytones in his urine. Could this be due to the recently tainted dog foods?