Prevention of Mold‐Induced Softening in Air‐Purged, Brined Cucumbers by Acidification

Mold‐induced cucumber softening was prevented in air‐purged fermentations by 0.16% acetic acid (equilibrated). Cucumber softening and pectate depolymerase activity increased in air‐purged fermentations when the level of acid was decreased to 0.12% and below. Mold‐induced softening was prevented in natural (not acidified) fermentations by delaying purging until indigenous microflora had reduced the brine pH to 4.0. Direct contact of air bubbles and cucumbers was not a requirement for subsurface mold growth. In air‐purged commercial brines softening was evidenced by soft spots and skin blisters on cucumbers acidified with 0.05 and 0.0%, but not with 0.16%, acetic acid. In broth culture, growth of four mold isolates from soft cucumbers was inhibited by 0.3% acetic (pH 4.0) but not by up to 0.9% lactic acid (pH 3.0) at 5.3% NaCl.