Diazinon reduction in apple juice using probiotic bacteria during fermentation and storage under refrigeration.

The main objective of this work was to study the effects of probiotic strains, probiotic primary inoculated population, concentrations of spiked diazinon, physiology of probiotic bacteria, fermentation times, and cold storage period in six consecutive stages on diazinon reduction in apple juice. Chemical properties (pH, total acidity, and sugar content), probiotic viability, and diazinon reduction percent were monitored during fermentation and cold storage. Dispersive solid phase extraction (dSPE) followed by gas chromatography-mass spectrometry was used to extract and measure diazinon concentration. Results showed that Lactobacillus acidophilus revealed the highest ability to reduce diazinon in apple juice after fermentation. Inoculation of L. acidophilus at 9 log CFU/mL showed significantly higher diazinon reducing ability than 7 log CFU/mL. L. acidophilus reduced diazinon in apple juice samples containing 1000 μg/L of spiked diazinon significantly higher than those containing 5000 μg/L. Heat-killed (dead) L. acidophilus bacteria reduced less diazinon content at the end of fermentation than viable bacteria. Furthermore, 72 h of fermentation was more effective in diazinon reduction. Spiked diazinon is completely disappeared at the end of cold storage (28 days) in treatments containing L. acidophilus, while the viability of probiotic bacteria required for causing health-promoting properties was maintained in apple juice.