The Food and Drug Administration said Wednesday that Applied Digital Solutions of Delray Beach, Fla., could market the VeriChip, an implantable computer chip about the size of a grain of rice, for storing medical information. The VeriChip itself contains no medical records, just codes that can be scanned and revealed in a doctor’s office or hospital. With that code, doctors can unlock part of a secure database that holds the patient’s medical information, including allergies and prior treatment. The electronic database, not the chip, would be updated with each medical visit.