2. Materials and methods
2.1. Plant material
Escarole (Cichorium endivia) and iceberg lettuce (Lactuca sativa L.) were selected for this study as the main characteristic leafy vegetables for fresh-cut salads. Plant material was purchased from a local wholesale market in Murcia (Spain) at the day of harvest and transported within 10 min under refrigerated conditions to the laboratory. Once in the laboratory, escarole and lettuce heads were stored in darkness overnight at 4 °C and 95% relative humidity (RH).
The core and outer leaves of whole heads were removed and discarded. Internal leaves were cut into 3 cm pieces with a sterile stainless steel knife. Shredded leafy vegetables were well mixed to obtain a homogeneous sample, and divided into different batches of 2 kg each per washing treatment. The whole process was conducted in a processing room at 8 °C under sanitary conditions. Two replications of each experiment, separately in time, were carried out between January and April. Results from one replication of each experiment are presented in this work, since similar tendencies were observed in both trials.