Quality of tomato (Solanum lycopersicum L.) fruits inoculated with Escherichia coli under different storage conditions

Abstract

The study evaluated the effect of storage temperatures of 7 and 22 °C for 168 h on tomatoes (Charleston cv.) inoculated with 107 CFU mL-1 of the enterotoxigenic Escherichia coli pathogroup (ETEC) strain on color indexes (hue angle, h°, and chroma, C*), firmness, titratable acidity (% citric acid), ascorbic acid, total soluble sugars and reducing sugars (glucose, fructose, and sucrose). ETEC survived with populations of 7 and 9.2 Log CFU g-1 at 7 and 22 °C, respectively until 120 h. Bacterial adherence and colonization under both storage conditions were confirmed by scanning electron microscopy. The index C* and ascorbic acid had higher values at 22 °C, while the parameters h°, firmness, and citric acid had lower values at the same storage temperature. At 7 °C, the concentration of total soluble sugars was affected; glucose and fructose showed lower values (0.054 and 0.057 g 100 g-1, respectively). Finally, the inoculated fruits exhibited significant differences in the parameters of consumer preference of fresh tomatoes such as color, firmness, sugars, and organic acids, which were affected depending on the storage temperature.