Electrical conductivity is a ratio of the substance density to electric field strength and is affected by the chemical composition of a substance. In ohmic heating terminology, the conductivity is a measure of the mineral or ionic content. For food substances, the most common ionic ingredient is salt (NaCl). The higher the amount of dissolved salts in a substance, the higher the conductivity.
Seawater has a conductivity measurement of ~5 S/m, whereas regular drinking water has a conductivity measurement of ~.0005 to .05 S/m . One method of measuring electrical conductivity is to use a TDS (Total Dissolved Solids) meter. TDS are the total amount of mobile charged ions in a substance (mg/L or ppm), calculated by measuring the number cations (positively charged) and anions (negatively charged) ions in the substance. Electrical conductivity is ~100 times the total number of cations and anions present