Efficient Sanitation Method of Jars Used for Fermenting Step of Korean Traditional Sauce Production

Introduction: Traditionally, the Korean soybean sauce/paste were placed and fermented in a jar for a certain period. It is very limited to clean and sanitize the jar because the use of detergent or sanitizer will cause the quality deterioration or off-odors. Other sanitation methods are also known hard to eliminate unfavorable microbes in jar.

Purpose: This study was to evaluate the efficiencies of sanitation methods applied for jar and to propose an effective treatment using the hot air by burning solid-fuels.

Methods: The inside and bottom surfaces of jars were swabbed using 3M pipette-swab before and after the treatments. The sanitation methods used commonly including straw fire, 30% alcohol, 20% liquor (soju), boiling water, baking soda solution and 2% solution of glacial acetic acid were applied to clean and sanitize the jars while the thermal treatment with solid-fuels was also evaluated. The number of total aerobic bacteria, lactic acid bacteria, and mold and yeast were analyzed by following method of Korea Food Code.

Results: The various treatment methods were shown to reduce the total aerobic bacteria only by maximum of one log CFU/100 cm²; boiling water treatment was 4.95 to 3.67 log CFU/100 cm² and 2% solution of glacial acetic acid for one hour immersion was 3.96 to 2.36 log CFU/100 cm², while a jar treated with heat of solid fuel was shown no growth of microorganisms from initial 4.59 log CFU/100 cm². Excessive use of solid-fuel could break the jar and thus, the proper ratio between solid-fuels and jar volume should be calculated to prevent the too high temperature to break a jar, such as about 70 g of solid-fuel for 20 liter and 280 g for 130 liter jars.

Significance: These results suggest an effective thermal treatment of jars, and therefore, it contributes to improve the hygienic management of jars used in traditional sauces fermentation process.