Recovery of bacterial spores dried on aluminium strips

Abstract

Bacterial spores dried on aluminium strips are used in microbiological validation of packaging and processing systems. Vortex agitation and sonication in Butterfield's buffer, 70% ethanol or O.lo/o Tween 80 were evaluated for ease of recovery of bacillus spores dried on aluminium strips to compare the concentration of dried spores to dilutions used to inoculate such strips. The highest recovery for Bacillus subtilis var. globigii spores was observed with sonication in 70% ethanol with average recovery close to the initial inoculum. The highest recovery for B. stearothermophilus spores was with sonication in Butterfield's buffer, averaging 0-8 log less recovery than the initial inoculum. Bacillus subtilis var. globigii spores were recovered from strips in greater numbers than B. stearothermophilus spores for all treatment medium combinations. Scanning electron microscopy revealed unrecovered spores adhering to strips after treatment. Recovery of B. subtilis var. globigii spores decreased with time over the 4 week storage period.

Comparative evaluation of methods for counting surviving biofilm cells adhering to a polyvinyl chloride surface exposed to chlorine or drying

“…This shows the importance of the choice of sonication bath and the necessity of specifying the characteristics of the ultrasound apparatus used to remove bacterial cells from a surface. These results are in agreement with published results showing the superiority of ultrasound over swabbing (Daufin and Sainclivier 1967) or over vortex agitation (Sugimoto et al. 1996).…”

Airborne movement of anthrax spores from carcass sites in the Etosha National Park, Namibia

“…The siting of collapsed spores may add yet more to our understanding of the topic. Collapsed spores of B. globigii dried on aluminium strips have been observed recently by others and thought possibly to represent non-viable members of the population (Sugimoto et al 1996). Similarly, in a study on the sporicidal effect of hydrogen chloride vapour on B. subtilis spores, Lelieveld (1980) attributed the collapsed state observed to loss of viability and to H ¦ neutralization of carboxyl groups in the cortex peptidoglycan responsible for the turgidity of the spore.…”

Antimicrobial Treatment of Heat Sensitive Materials by Means of Atmospheric Pressure Rf‐Driven Plasma Jet

“…An established procedure was used to test the recovery of micro organisms [10,11]. Briefly, test strips were transferred into sterilized test tubes containing 5 mL sterile sodium chloride solution 0.9 % with 0.1 % Tween 80 (Prolabo/VWR international) as well as 10 sterile glass spheres (5 mm diameter), each, and agitated for 20 min on a shaking machine (Bühler shaker KL 2) with a frequency of 420 min −1 .…”

“…Antimicrobial plasma effects have been tested using polyethylene strips contaminated punctually (diameter of the area: 4-5 mm) with 25 µL of a use-dilution suspension of Escherichia coli or Bacillus atrophaeus spores, respectively, and dried under aseptic conditions (laminar flow) for at least 1 h. The mean contamination rate was 2·10 6 cfu/strip for B. atrophaeus spore strips (n=15) and 6·10 5 cfu/strip for E. coli strips (n=24). An established procedure was used to test the recovery of micro organisms [10,11]. Briefly, test strips were transferred into sterilized test tubes containing 5 mL sterile sodium chloride solution 0.9 % with 0.1 % Tween 80 (Prolabo/VWR international) as well as 10 sterile glass spheres (5 mm diameter), each, and agitated for 20 min on a shaking machine (Bühler shaker KL 2) with a frequency of 420 min −1 .…”