U.S. federal officials are investigating an apparent link between ground turkey meat and a nationwide outbreak of salmonella illness, according to media reports Wednesday. Such illness has so far killed one person in California and sickened at least 76 others in 26 states. Yet no meat has been recalled. Federal officials said the evidence found so far pointed to a single ground turkey factory, but they declined to identify it or the company involved. However, the meat processor Cargill said that it had been contacted by the U.S. Department of Agriculture and asked to provide information as part of the salmonella investigation. Neil Gaffney, a U.S.D.A. spokesman, said in an e-mail that so far, there was not enough evidence that “conclusively links these illnesses to any specific product or establishment. Without specific enough data, it would not be appropriate to issue a recall notice.” Ground turkey is a popular substitute for ground beef for grilled burgers. It is said that many people might have turned to ground turkey because they think it is healthier or safer than ground beef, which has been associated with illness outbreaks caused by E. coli, also bacteria. It is not illegal to sell meat contaminated with salmonella; cooking the meat thoroughly can destroy the pathogen.