Location: Food Quality Laboratory
Title: Temperature abuse timing affects the quality deterioration of commercially packaged ready-to-eat baby spinach Authors
Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 30, 2013
Publication Date: January 20, 2014
Citation: Kou, L., Luo, Y., Park, E., Turner, E.R., Barczak, A., Jurick II, W.M. 2014. Temperature abuse timing affects the quality deterioration of commercially packaged ready-to-eat baby spinach. Postharvest Biology and Technology. 91:96-103. Interpretive Summary: Storing packaged ready-to-eat baby spinach leaves at elevated temperature may cause quality loss and thus translates into decreased profits for processors and retailers. However, the effect of elevated temperature timing and duration on product quality is unknown. Scientists at the USDA-ARS Food Quality Laboratory examined the effect of elevated temperature scenarios on product quality and shelf life for packaged baby spinach. The findings show that storage life of commercially packaged baby spinach products can be significantly extended by maintaining the product temperature at 1 °C - 4 °C. Also, when the elevated temperature occurred later in the product shelf life, it had a more detrimental effect on product quality than when it occurred shortly after processing. This study provides critical scientific information for food processors, distributors, and retail store managers in developing improved cold chain management strategies for maintaining the quality and shelf life of packaged fresh-cut vegetables.
Technical Abstract: Temperature abuse of fresh-cut products occurs routinely during transportation and retail store display. However, the stage of product shelf life during temperature abuse and its impact on sensory attributes and product quality have not been studied. This study evaluated the effect of temperature abuse occurring immediately after processing and late in shelf life through measurements of sensory attributes, color, and membrane integrity of commercially packaged baby spinach. The packaged baby spinach were received within 2 days of processing, and immediately placed at 1, 4, 8, 12, 16 and 20 °C storage. Additional samples were stored at 1 °C for six days, and then transferred to 4, 8, 12, 16 and 20 °C to emulate late-stage temperature abuse. Package headspace gas composition, product tissue electrolyte leakage, color and sensory attributes (visual quality, purchase intent, off-odor, decay, texture and overall quality) were evaluated every 1-2 days up to 16 total. Results indicate that when the product temperature was maintained at 1-4 °C, the quality of commercially packaged baby spinach can be retained for up to 18 days post-processing. However, temperature abuse scenarios occurring at 8 °C or above significantly (P < 0.001) shortened product shelf life as exhibited by accelerated tissue electrolyte leakage, product yellowing, decay and off-odor development. The timing of temperature abuse significantly affected the response of the product as evidenced by changes in several different quality indicators. Temperature abuse occurring at the late stage had a more pronounced effect on product quality loss than that when it occurring shortly after processing. Data from this study demonstrates that good cold-chain practices throughout the storage life of the product are critical for maintaining the overall quality of fresh-cut baby spinach.