Antimicrobial effects of pulsed electromagnetic fields from commercially available water treatment devices – controlled studies under static and flow conditions

Abstract

BACKGROUND Pulsed‐electromagnetic field (PEMF) devices are marketed and utilized for the non‐chemical management of biofouling, with little scientific validation of their effectiveness. Proof‐of‐principle studies were carried out previously to systematically investigate the effect of two such commercial devices on the culturability of bacteria under controlled static (i.e. non‐flowing) conditions and anti‐microbial effects were demonstrated. However, such effects were small and an expanded investigation, using these devices and including the effect of flow, was deemed necessary. RESULTS The effect of the electromagnetic fields generated by the same two commercial devices on the bacterial culturability of Escherichia coli and Pseudomonas fluorescens under flow conditions has been contrasted with previous static results. It has been found that the effectiveness of PEMF exposure depends on waveform, extent of flow, type of bacteria and PEMF exposure duration. CONCLUSION Both stimulatory and inhibitory effects are observed that are uniquely dependent upon device type (i.e. a range of parameters including waveform), species of microorganism, presence and degree of flow and PEMF exposure time. For both devices and both microorganisms, stimulatory effects are uniformly observed for one device under static conditions and inhibitory effects are uniformly observed for the other device at low flow and for the former at high flow. © 2017 Society of Chemical Industry

Low-frequency electromagnetic fields as an alternative to sanitize water of drinking systems in poultry production?

“…Other studies have shown that the direct application of weaker electromagnetic fields (≤ 100 Hz; ≤ 1 mT) on bacterial cultures may have not only reductive [24, 25, 32], but also neutral [21, 34], or even stimulatory effects on bacterial cell growth [19, 20]. Interestingly, Piyadasa et al [35] reported that both stimulatory and inhibitory effects could be observed on the culturability of Escherichia coli and Pseudomonas fluorescence by 7 h exposure to pulsed electromagnetic fields under copiotrophic conditions. Latter authors showed that outcomes were influenced by water flow conditions (static vs. low flow vs. high flow) and differed between the two commercial devices used [35].…”

“…Interestingly, Piyadasa et al [35] reported that both stimulatory and inhibitory effects could be observed on the culturability of Escherichia coli and Pseudomonas fluorescence by 7 h exposure to pulsed electromagnetic fields under copiotrophic conditions. Latter authors showed that outcomes were influenced by water flow conditions (static vs. low flow vs. high flow) and differed between the two commercial devices used [35]. Therefore, we assume that the bacterial microbiota of circulatory systems may have been exposed to a different treatment regime, which induced temporarily an increase of colony counts, especially of heterotrophic bacteria growing at 36°C.…”

Review of Techniques to Reduce and Prevent Carbonate Scale. Prospecting in Water Treatment by Magnetism and Electromagnetism

“…In the experiments of Piyadasa et al (2018) [84], it was observed that electromagnetic fields generate a great variety of positive or negative adaptive responses of different microorganisms, under various conditions. The interactions of some factors such as the type of microorganism, the specifications of the device generating the electromagnetic field (waveform, frequency, intensity, etc.…”

Simulation study of Cell Transmembrane Potential and Electroporation Induced by Time-Varying Magnetic Fields

“…TMFs, including PMFs and oscillating magnetic fields (OMFs), are an emerging non-thermal technique in the food processing industry [1, 2, 3], which can maximize the preservation of food appearance, flavour, texture, and nutritional quality, and improve the freezing process and quality of fresh ground beef [4], chicken breast [5], blueberries [6], cucumber [7], etc. In terms of bactericidal effect, PMF can be used to inhibit and destroy microorganisms such as Escherichia coli [8, 9, 10], yeast [11], and Staphylococcus aureus [12].…”