STERIS Corp., Mentor, Ohio, will add a Principal REIT separate account and the American Funds Growth Fund of America and Vanguard U.S. Value and Explorer mutual funds as investment options in its $192 million 401(k) plan, said Bob Becker, employee benefits director. Trustees are adding the options to fill style gaps, Mr. Becker said. The plan will offer 13 investment options, up from nine. Principal Financial is the bundled provider. Hartland & Co. assisted.