Thermal destruction of Clostridium botulinum spores suspended in tomato juice in aluminum thermal death time tubes

Abstract

The heat destruction characteristics of Clostridium botulinum spores suspended in tomato juice and phosphate buffer were determined by the survivor curve method with aluminum thermal death time tubes. Two type A strains of C. botulinum and a type B strain were evaluated. Strains A16037 and B15580 were implicated in outbreaks of botulism involving home-canned tomato products. Strain A16037 had a higher heat resistance than either 62A or B15580. The mean thermal resistance (D-values) for A16037 in tomato juice (pH 4.2) were: 115.6°C, 0.4 min; 110.0°C, 1.6 min; and 104.40C, 6.0 min. The mean D-values for A16037 in Sorensen 0.067 M phosphate buffer (pH 7) were: 115.6°C, 1.3 min; 110.0°C, 4.4 min; and 104.4°C, 17.6 min. At each test temperature, the D-values were approximately three times higher in buffer than in tomato juice. The zvalue for C. botulinum A16037 spores in tomato juice was 9.4°C, and in buffer the z-value was 9.9°C. The use of aluminum thermal death time tubes in a miniature retort system makes it possible to determine survivor curves for C. botulinum spores at 121.1°C. This is possible because the lag correction factor for the aluminum tubes is only about 0.2 min, making possible heating times as short as 0.5 min. MATERIALS AND METHODS Spores. Cultures of a C. botulinum type A strain, A16037, and a type B strain, B15580, were obtained from the Center for Disease Control in Atlanta, Ga. These strains were implicated in outbreaks of botulism in which home-canned tomato products were the toxin-carrying vehicle (7, 8). The classical 62A strain was obtained from the American Type Cul-23

INACTIVATION OF CLOSTRIDIUM BOTULINUM TYPE E SPORES BY HIGH PRESSURE PROCESSING

“…Sorensen phosphate buffer (0.067 M, pH 7.0) was prepared by mixing 610 mL of a stock solution of 0.067 M sodium phosphate dibasic anhydrous (Na,HPO,) with 390 mL of a stock solution of 0.067 M potassium phosphate monobasic anhydrous (KH,PO,) (Odlaug and Pflug 1977). The buffer was dispensed in 1 50-mL quantities and sterilized by autoclaving at 121C for 10 min.…”

Partial purification, characterisation and thermal inactivation kinetics of peroxidase and polyphenol oxidase isolated from Kalipatti sapota (Manilkara zapota)

“…In the present study, POD was found to be the most heat stable enzyme in sapota with a Z-value of 17.6 ∘ C. The Z-value was observed to be higher than the reported Z-value (9-10.7 ∘ C) for C. botulinum spores in various matrices. 38 Therefore, considering D-and Z-values of the enzymes along with D-and Z-values of microorganisms during fruit processing can hold better promise for producing stable products with improved shelf life.…”

Heat Induced Browning of Clarified Apple Juice at High Temperatures

“…THE TECHNIQUE of heating small samples of foods in glass and aluminum tubes or plastic bags to simulate the effect of heat on quality has been widely used (Farkas, 1962;Odlaug and Pflug, 1977;Erdtsieck and Beumer, 1976). Saguy et al (1978a) used a more sophisticated steam-heated thermal unit.…”