THE EFFECT OF PHENYLGLYOXAL ON CLOSTRIDIUM-SPOROGENES

In general phenylglyoxal (PG) was found to inhibit anaerobic bacteria, with strict anaerobes being more affected than facultatives. The susceptibility of Clostridium sporogenes vegetative cells to PG varied with the type of medium (20->10 000 ·g ml-1 PG), pH (20->2500 ·g ml-1 PG), and incubation temperature (625-1250 ·g ml-1 PG). However, optimum vegetative (20 ·g ml-1 PG) and spore (<1-0 ·g ml-1 PG) inhibitions occurred in cooked meat medium for all conditions tested. PG was most active against vegetative cells at pH values >7.5 and at temperatures between 25-30°C. The compound inhibited sporogenesis (156 ·g ml-1 PG) and replication processes (29 ·g ml-1 PG), as well as deoxyribonuclease activity (4.28 ·g ml-1 PG). Increased concentrations of free α-amino acids and sulfhydryl-containing compounds antagonized the activity of PG against vegetative cells. Antigerminative effects appeared to occur optimally at low pH, and the heat resistance of C. sporogenes spores was reduced. Furthermore, PG concentrations of 10-0.63 ·g ml-1 prevented germination of C. sporogenes spores in five commercial soups and maintained their organoleptic qualities for 35 days at 30°. © 1993 Academic Press Limited.