Hot water, sodium carbonate, and sodium bicarbonate for the control of postharvest green and blue molds of clementine mandarins

Clementine mandarins cv. ‘Clemenules’, artificially inoculated with Penicillium digitatum or Penicillium italicum, were immersed in 0, 2, or 3% (w/v) sodium carbonate (SC) solutions at 20, 45 or 50 °C for 60 or 150 s. Decay incidence was determined after 7 days of storage at 20 °C and 90% relative humidity (RH). Hot water (HW) at 45 or 50 °C did not satisfactorily control both diseases. SC significantly enhanced decay control compared to water alone at all temperatures and for all immersion periods. Heated SC solutions were more effective than solutions at 20 °C. A 150 s dip in 3% SC at 50 °C totally controlled both green and blue molds without noticeably injuring the fruit. SC at 50 °C significantly reduced the incidence of both green and blue molds on mandarins stored at 3.5 °C for 60 days. Both diseases were reduced by 40–60% on mandarins dipped for 60 or 150 s in 2 or 3% sodium bicarbonate (SBC) solutions at room temperature. The effectiveness of all HW, SC, and SBC treatments on clementines was inferior to that obtained on oranges or lemons in related previous work.