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BMC Microbiology
Research
Elf
Bioeffects
Eight hours in millitesla magnetic fields raised oxidative stress and DNA fragmentation in probiotic bacteria, Turkish study finds
Researchers at Yozgat Bozok University in Türkiye exposed six probiotic Lactobacillus and Lacticaseibacillus strains to 50 Hz alternating or direct-current magnetic fields of 1.62 to 2.61 millitesla for eight hours. Oxidative stress markers and DNA fragmentation rose with field intensity in all six strains, while culture turbidity also rose, so the authors call the fields sublethal stressors rather than cytotoxic agents. The exposures are industrial in scale: 2.61 millitesla is roughly 13 times the 200 microtesla public reference level in
ICNIRP's 2010 low-frequency guidelines (Table 4, page 827). In March we covered
the same pattern at a very different frequency, where 2.45 GHz Wi-Fi-band radiation induced oxidative stress in human skin bacteria.
Exposure note: Fields were produced by a Helmholtz coil system of 154 turns and 20 cm radius, with the cultures on the central axis 10 cm from each coil face, at a drive current of 3.0 A. The intensity steps were 1.62, 2.13, 2.50 and 2.61 millitesla, applied for eight hours. Controls sat about 150 cm away in a residual field of 0.97 Gauss, roughly 0.097 millitesla, which the paper treats as the Earth's background. For scale, the 2010 ICNIRP low-frequency guidelines set a 200 microtesla reference level for public exposure to 50 Hz magnetic fields, so every exposed step here is above that and the top step is about 13 times it.
Quotes
"Low-intensity AC and DC magnetic fields induced significant oxidative and genotoxic responses that were governed primarily by magnetic field intensity rather than field type."
— Ülker et al., BMC Microbiology (2026)
"Therefore, the observed increases in OD600 should be interpreted as changes in culture turbidity rather than definitive evidence of increased bacterial proliferation."
— Ülker et al., BMC Microbiology (2026)
"In addition, long-term recovery experiments and mutation assays were not performed; therefore, it remains unclear whether the observed DNA damage is fully reversible or may result in persistent genetic alterations following prolonged or repeated magnetic field exposure."
— Ülker et al., BMC Microbiology (2026)
Exposure
"To eliminate potential thermal interference from the coils, the ambient temperature was strictly monitored and maintained at room temperature (25 ± 1 °C) throughout the 8-h exposure period."
— Ülker et al., BMC Microbiology (2026), Methods
Location
📍 Turkey
📄 Underlying Research
Low-frequency magnetic fields induce oxidative and genotoxic stress and growth stimulation in lactic acid bacteria
Ülker U, Aydın A, Karan T, Kanbur Çavuş H, Şahingöz R
(2026)
BMC Microbiology
Journal Level 1ⓘ
