More than 40% of the nation's 15,000 nursing homes do not meet sanitary standards for food and more than a quarter fail to administer drugs properly, according to the government's first consumer guide to nursing homes. The guide will be released next week. More than 1.5 million people are cared for in the nation's nursing homes. The guide, the brainchild of William L. Roper, who administers the Medicare and Medicaid programs, shows how each of the 15,000 nursing homes scored on 32 health, safety and care standards. The ratings are based on periodic inspections required by federal law and performed by state agencies.