GLUCONO-DELTA-LACTONE AND CITRIC-ACID AS ACIDULANTS FOR LOWERING THE HEAT-RESISTANCE OF CLOSTRIDIUM-SPOROGENES PA-3679 IN HTST WORKING-CONDITIONS

The heat resistance of Clostridium sporogenes PA 3679 spores has been studied to establish the influence of acidification with glucono-delta -lactone (GDL) and citric acid on the thermal resistance parameters (D -T and z) of this microorganism and to compare their effect with phosp hate buffer and natural asparagus as reference substrates. A reduction in D-T values was observed in asparagus puree as the acidification le vel increased with both acidulants although this effect was more evide nt at the lower treatment temperatures studied (121-127 degrees C). Ci tric acid was more effective for reducing the heat resistance of spore s than GDL at all of the temperatures. The reduction in pH diminished the value of the 2 parameter, although it was necessary to lower the p H to 4.5 to obtain a significant reduction.