The effect of vinegar and drying (Solar and Open Sun) on the microbiological quality of ginger (ZINGIBER OFFICINALE ROSCOE) rhizomes

This study evaluated the influence of 10% vinegar and solar drying using two solar dryers and open-sun drying on the microbiological quality of ginger (Zingiber officinale Roscoe) rhizome. The rhizomes were analyzed for bacterial, mold, and Salmonella populations in the raw state, which were water-washed and soaked in 10% vinegar, and in dried form. The fungal population was isolated and identified. Fresh and dried ginger rhizome contained both bacterial and fungal population in the range of 3.0 x 10² ± 1.14 x 10² to 2,180 x 10⁹ ± 70.7 x 10⁹ CFU/g. The stainless steel solar dryer had fewer fungal loads among the drying methods. Aspergillus and Penicillium species of mycotoxin-producing potential were identified. The 10% vinegar as pretreatment showed no significant difference (p ≤.05) in the bacterial population reduction but in the fungal population reduction. Growth of fungi in fresh and dried ginger extracts was lower compared with growth in Potato Dextrose Broth.