Modification of the Processing Method for Home-Preservation of Tomato Juice

Abstract

A modification (low water level bath, LWL) of the recommended water bath (high water level bath, HWL) procedure was used to process tomato juice in quart jars. The LWL bath contained one-fifth the amount of water recommended for the HWL bath. Use of the HWL bath required 59 min and 1838 watt-hours of electricity to heat the bath and process hot packed (92°C) juice for 15 min. In comparison, 34 min and 1065 watt-hours of electricity were required when the LWL bath was used. Samples of juice were inoculated with log 3.0 Bacillus coagulans per ml, processed in each of the two baths, and stored up to 12 weeks at 27°C. Aerobic mesophiles were found only in juice processed in the HWL bath and stored 4 weeks and in juice processed in the LWL bath and stored 0 weeks. The aerobic mesophile count (log10) of juice processed in the HWL bath and stored 4 weeks was a mean log 1.4 per ml. Similar juice processed in the LWL bath had a mean log 1.3 aerobic mesophiles per ml. Juice processed in both water baths and stored for 8 and 12 weeks exhibited mesophilic counts of <1 log per ml. None of the inoculated, processed samples had a mean count greater than 1 log per ml of juice for aerobic, acid forming mesophiles; aerobic thermophiles; anaerobic mesophiles and thermophiles; and mold. Using temperature values and microbiological measurements, one may conclude that the LWL bath was as effective as the HWL bath for processing tomato juice while allowing for a substantial saving of time and electricity.