Carl M. Olsen · 1965
Viable spore counts dropped from about 1,486 to 0.143 colonies per plate for Penicillium and from about 2,000 to 0.188 for Aspergillus niger, while Rhizopus growth fell from fully covered plates to 21.4% of plates showing growth. Non-inoculated microwave-treated loaves remained nearly free of mold for 21 days, whereas untreated loaves with preservative were fully moldy within 12 days. Microwave treatment was far more effective than sodium propionate at preventing mold growth.
L. Miro, H. Atlan, Y. Arnaud, G. Deltour, R. Loubiere · 1965
The study used a strain of Escherichia coli cultured in a nutritive medium and split into two Roux flasks. The flasks were kept for 60 hours with agitation 4 or 5 times daily and no temperature rise was observed. Survival was identical at 6,000 roentgens, increased at least tenfold at 24,000 and 48,000 roentgens, and mortality was similar again at 72,000 roentgens; the authors stated they did not intend to draw conclusions.
Philip Schmidt · 1964
Clostridium welchii type A toxin showed no change in toxicity when tested by human serum opacity and mouse lethality studies. Flocculation tests found no change in antitoxin combining capacity or antigenicity of diphtheria toxin. The authors questioned the efficacy of available assay procedures and called for more precise methods.
Donald E. Barber · 1962
The study used the luminescent bacterium Photobacterium fischeri exposed to continuous-wave microwaves at 12.8 Mc intervals between 2608.7 and 3082.3 Mc. Initial measurements suggested reduced luminescence in exposed samples, but the difference was traced to Pseudomonas contamination from distilled water used to rinse the apparatus. After sterilizing the system and using sterile water, no significant difference in luminescence between exposed and control suspensions was observed 20 to 24 hours post-exposure.
Edwin Lorenz Carstensen · 1962
A. A. TEIXEIRA-PINTO et al. · 1960
George H. Brown, Wendell C. Morrison · 1954
O. Cimitan · 1951
Maurizio Terni, Pietro Lombardini · 1951
S. E. Jacobs, Margaret J. Thornley, P. Maurice · 1950
Researchers exposed various bacteria, principally Bacterium coli and Staphylococcus aureus, to high-frequency electric fields at 1-65 Mc/s with external electrodes while preventing lethal temperature rise. They used a low-powered variable-frequency generator (1-710 Mc/s) and a high-powered 44 Mc/s diathermy unit. Bacterial survival was judged by viable plate counts using duplicate samples. No significant mortality occurred in any experiment, even at high voltage gradients. The results consistently failed to confirm Fleming's 1944 report of high mortality.
H. Schaefer, H. Schwan · 1947
Ed. Gilles · 1944
E. Gilles · 1944
Hugh Fleming · 1944
Wilhelm Krasny-Ergen · 1936
Conrad K. Gale · 1935
Liebesny, P. · 1934
Dr. W. Haase, Dr. E. Schliephake · 1931
Dr. W. Haase, Priv.-Doz. Dr. E. Schliephake · 1931
Unknown authors
Researchers exposed Salmonella typhimurium to 2.45 GHz amplitude-modulated microwave radiation at an average specific absorption rate of approximately 2.5 mW/g in a waveguide inside a 37°C incubator. Stationary-phase and log-phase bacteria were exposed for three hours, and stationary-phase bacteria were also exposed for 24 hours. No effect on viability or mutation frequency was seen after three-hour exposure, but one of five strains exposed for 24 hours showed reduced viability and increased mutation frequency compared with a 37°C control, though not compared with a 39°C control. Reconstruction experiments found the vial temperature inside the waveguide was about 1.5°C higher than the incubator temperature, which could explain the observed changes.
Unknown authors
Unknown authors
Colicin production was enhanced only at 5.8 mm (51.7 GHz) at 25°C and 37°C, doubling after 60 minutes at 37°C and 0.5 mW/cm². Plaques observed ranged from .2 to .8 mm in diameter, and small amounts of colicin were also produced in unirradiated colonies.
Unknown authors
Researchers exposed E. coli C-600 with a tonA defect to 1.07 GHz capacitor-fed fields in Brain Heart Infusion medium. At 42°C the bacteria became susceptible to phage T5 infection, showing nearly complete lysis and virus production when phage was added immediately after exposure. Field exposure of bacteriophage T5 suspended in BHI resulted in 80% inactivation in 2 minutes at 37°C, while the phage is normally stable to temperatures in excess of 480°C. E. coli was more easily inactivated by RF fields than by temperature alone, as 90 minutes at 48°C produced only a minimal reduction in viability.
Tomberg, V.
The study investigated the influence of short electrical waves on living organisms at wavelengths less than 8 meters. The principal effect in both magnetic or electric fields was Joule's heat.
Unknown authors
Researchers conducted preliminary testing of magnetic field mutagenicity using bacterial systems with field strengths ranging from 0.1 to 1.1 Tesla. Salmonella strain TA98, which mutates by frameshift, did not show an increase in mutation frequency. Initial tests with E. coli, B. subtilis, and Photobacterium fisheri also produced suggestive data of increased mutation frequencies.
