Effect of Sodium Polyphosphates on Growth of Listeria monocytogenes

Abstract

Evaluation of sodium polyphosphates (SPP), multifunctional food additives, indicated that only the higher polymers sodaphos, hexaphos, and glass H (average chain length = 6, 13, and 21, respectively) significantly inhibited growth of Listeria monocytogenes. The effect of the three compounds (0–2%) on growth of L. monocytogenes was studied in brain heart infusion + 0.3% glucose medium, pH 6.0, at 28, 19, 10, and 5°C. The organism grew well under all test conditions in the absence of SPP. Hexaphos and glass H were considerably more inhibitory than sodaphos. The most pronounced effect of SPP was on lag times, which increased with increasing SPP concentration and decreasing temperature. At 10°C, addition of 0.3% hexaphos or glass H increased lag time from 22 h to 197 and 186 h, respectively, and no growth was observed after 40 d in the presence of 2.0% of these compounds. Addition of 2.0% NaCl increased the inhibitory effect of SPP but had little effect on growth in SPP-free media. Results suggest that high molecular weight SPP may be useful in controlling the growth of L. monocytogenes, particularly at low temperatures and in combination with NaCl.