Inhibition of Bacterial Histamine Production by Sorbate and other Antimicrobial Agents

Potassium sorbate at a concentration of 0.5% inhibited growth and histamine production by selected strains of Proteus morganii and Klebsiella pneumoniae in a trypticase-soy broth fortified with histidine (TSBH medium). At 32°C, the inhibition was effective for up to 120 h of incubation; at 10°C, the inhibition was observed through 216 h of incubation. Sodium hexametaphosphate and sodium polyphosphate did not inhibit growth of these histamine-producing bacteria at 32°C, but did slow the rate of histamine production at the 2% level. The extent of reduction of bacterial histamine production by sodium hexametaphosphate and sodium polyphosphate was most pronounced for P. morganii . Sodium chloride at levels up to 2.0% was ineffective in preventing bacterial growth and histamine production.