Impact of storage time and temperature of salad heads on the quality of fresh-cut Cichorium endivia

The impact of temperature and storage time of escarole salad heads on the quality of processed, fresh-cut salad was investigated. Based on temperatures recorded in a fresh-cut processing plant, salad heads were stored for four different storage times (0, 5, 9, and 12 d) at four temperatures (4, 7, 10, and 12 °C) before being processed. A range of quality criteria (technical yield, global visual aspect, pink cut surfaces, mechanical texture, aerobic microflora, respiration rate, atmosphere composition in fresh-cut salad pouches, nuclear magnetic resonance transverse relaxation time) were measured on processing day, after 7 d storage at 4 °C of the fresh-cut salad packaged in pouches, and 1 d after pouch opening. The results are presented for salads grown in southeast France and early-season harvest, validated by experimental repetitions with a late-season harvest and salads from another geographical origin. Storage of salad heads caused deterioration of all quality attributes except for total aerobic bacteria. The global visual aspect was the most sensitive to changes in storage conditions of salad heads (significant reduction in quality for 5 d over 7 °C). In contrast, mechanical texture (maximum load for the shear test) was only significantly different for the fresh-cut salad prepared from salad heads stored for 9 d at 12 °C. For all quality criteria, fresh-cut salads processed from salad heads stored for 5 d at 4 and 7 °C were not significantly different from those of non-stored salad heads. For storage time of 5 d or less, a temperature of 7 °C is likely as good as 4 °C for escarole salad-head storage intended for fresh-cut processing.