Heated scallop-shell powder slurry treatment of shredded cabbage.
The main component of scallop-shell powder is calcium carbonate (CaCO3). Through heat treatment, CaCO3 in the shell is converted to CaO, which exhibits antibacterial activity. The disinfecting effect of heated scallop-shell powder on shredded cabbage was investigated for various powder concentrations (0.1 to 1.0 g dm(-3)) and treatment temperatures (10 to 40 degrees C). Scallop-shell powder treatment was found to reduce the aerobic bacteria count in cabbage, with increasing effectiveness at higher powder concentrations and treatment temperatures. Coliforms were completely eliminated within 5 min with as little as 0.1 g dm(-3) powder treatment. During storage at 4 degrees C, aerobic bacterial counts did not increase after powder treatment, whereas counts increased with water-washing or sodium hypochlorite treatment at 200 microg dm(-3). The inactivation pattern of bacterial cells in shredded cabbage involved an accelerated decline followed by an extended tail at powder concentrations of 0.1 and 0.5 g dm(-3). We postulate that a fraction of bacterial cells in the initial population becomes tolerant to the shell powder. A proposed model accurately predicts the reducing bacterial counts on shredded cabbage by scallop-shell powder treatment. The decrease in the L-ascorbic acid content of shredded cabbage was approximately 20 to 30% for scallop-shell powder treatment at 0.1 and 0.5 g dm(-3) (20 degrees C), which is almost identical to that by sodium hypochlorite treatment at 200 micorg dm(-3).
Sawai
J
J
Department of Applied Chemistry, Kanagawa Institute of Technology, Atsugi, Japan. sawai@chem.kanagawa-it.ac.jp
Satoh
M
M
Horikawa
M
M
Shiga
H
H
Kojima
H
H
D001420:Bacteria, Aerobic / Q000187:drug effects* / Q000254:growth & development; D001937:Brassica / Q000382:microbiology*; D002119:Calcium Carbonate / Q000737:chemistry; D017610:Calcium Compounds / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006358:Hot Temperature; D010087:Oxides / Q000494:pharmacology*; D013696:Temperature
D017610:Calcium Compounds; D004202:Disinfectants; D010087:Oxides; C016538:lime; D002119:Calcium Carbonate