EFFECT OF HIGH-INTENSITY PULSED ELECTRIC FIELDS ON SURVIVAL OF ESCHERICHIA COLI K-12 SUSPENDED IN MEAT INJECTION SOLUTIONS

Survival of Escherichia coli K12 suspended in solutions used for enhancing meat products after high-intensity pulsed electric field (PEF) treatments was examined. Solutions were prepared to provide 0.3% salt, 0.3% phosphate and/or 0, 1, 2 or 3% sodium lactate in a finished product enhanced to 110% of initial weight. Therefore, enhancement solutions contained water, 3% NaCl, 3% phosphate and/or 0, 10, 20 or 30% sodium lactate. Samples containing 0.1% NaCl were run as controls. Single PEF strengths used for PEF treatments were 12.5, 7.0, 6.0, 5.0 and 3.5 kV/cm. For 12.5, 7.0 and 6.0 kV/cm, two levels of pulse controller resistance were used, oc and 200 ohm; for 5 and 3.5 kV/cm, only 200 ohm was tested. Above 7 kV/cm, arcing occurred which limited the application of this technology in these solutions. Electrical field strength at 7 kV/cm with a pulse controller resistance of 200 ohm resulted in a reduction of about 2 log cfu/mL when cells were suspended in the enhancement solution containing no lactate. Lower electrical field strengths (≥6 kV/ cm) were generally ineffective.