aSmagnetic field = static magnetic field; Omagnetic field = oscillating magnetic field
Hoffman (1985) reported on the inactivation of microorganisms with OMF in milk, yogurt, orange juice, and bread roll dough. According to Hoffman (1985) only 1 pulse of OMF was adequate to reduce the bacterial population between 102 and 103 cfu/g. The intensity of the magnetic field required to achieve these effects varied between 2-25 T and a frequency range from 5-500 Hz.
A review of the literature shows that inconsistent results have been obtained on the effect of OMF on microbial growth (Table 1). In some cases OMF stimulated or inhibited microbial growth and, in others, it had no effect on microbial growth. The results presented in Table 1 show that, although not well understood, the effect of magnetic fields on the microbial population of foods may depend on the magnetic field intensity, number of pulses, frequency and property of the food (that is, resistivity, electrical conductivity, and thickness of the foodstuff).