Microbial Safety, Quality and Shelf-Life of Fresh Produce and Other Ready-to-Eat Foods

This project contains the following two primary objectives - 1) assess the survival of eight Lm strains grown planktonically or as a biofilm on three unwaxed apple varieties (Gala, Granny Smith, Honeycrisp) from two different harvest seasons and three different growing regions (Michigan, Washington, Pennsylvania) during air (21% O2) or controlled atmosphere (1.5% O2, 0 - 3% CO2) (CA) storage, and 2) assess Lm survival on these same apples after waxing. These two objectives are based on the following underlying hypotheses: 1) Lm will not grow on the apples but may persist on surface-inoculated apples for several months during storage, 2) The extent of Lm survival on apples will vary based on strain of Lm, physiological state (i.e. derived from planktonic cells vs. biofilm) of Lm, apple variety, growing region, growing season and type of storage (air, controlled atmosphere), and 3) Waxing of apples may enhance the survival of Lm.