The effect of low static magnetic field on bacterial growth were studied using three bacterial strains (Escherichia
coli, Staphylococcus aureus and Bacillus subtilis). The bacterial cultures were cultivated in a nutrient agar
medium and incubated at 37°C for 24 hours, and then bacterial colonies were picked by a loop and inoculated in
10 ml nutrient broth. Each bacterial culture was subjected to different magnetic fields (30, 50 and 80) mT. The
magnetic fields were measured by Teslameter (model F.W.Bell 4048) in Physics Department, faculty of Science,
Al al-Bayt University, Mafraq, Jordan.
In this work 0.1 ml of stock bacterial suspension was inoculated into four groups in tubes each contains 5 ml of
nutrient broth. Three groups of tubes were subjected to magnetic fields (30, 50 and 80) mT respectively. While
the fourth group was used as a negative control (no magnetic field was subjected). All tubes were incubated at 37
ºC for 24 hours. The effects of different magnetic fields on growth rate were evaluated by measuring the optical
density at 600 nm using spectrophotometer (JENWAY 6300) (Fouad et al. 2014).
On the other hand, a serial dilution using the bacterial culture was performed to determine the colony forming
unit (CFU) value per ml. A volume of 100 µl of a (1x106
) dilution factor was inoculated in agar plates by spread
plating. Several plates were made for more accuracy. After incubation, the colonies formed on the plates were
visually counted.