Spore-forming bacteria in commercial cooked, pasteurised and chilled vegetable purees

In commercial purees of broccoli; carrot, courgette, leek, potato and split pea, pasteurized in their final packaging and analysed at two periods, Bacillus spp were the dominant aerobic mesophilic bacteria (AMB). Initial numbers were generally lower than 2 log cfu g(-1). They increased up to 6-8 log cfu g(-1) after about 20 days of storage at 10 degrees C. At 4 degrees C, numbers of AMB after 20 days were lower than 3 log cfu g(-1) in potato puree, lower than 4 log cfu g(-1) in leek puree, and between 3 and 6 log cfu g(-1) in other products. Strict anaerobes were in markedly lower numbers than AlWB. At all storage temperatures tested courgette puree usually showed the most rapid bacterial growth and spoilage. On this product, an increase in storage temperature from 4 degrees C to 10 degrees C resulted in a threefold reduction in time to 5 log cfu g(-1) and time to spoilage. Growth kinetics of AMB in courgette puree at 20 degrees C, 15 degrees C, 10 degrees C, 6.5 degrees C and 4 degrees C were determined using a mathematical model. Three hundred and forty eight isolates were identified using the APl system. Bacillus circulans, B. macerans and B. polymyxa were among the main species isolated from products stored at 4 degrees C and 10 degrees C, while B, subtilis and B. licheniformis were the dominant species in product stored at abuse temperature Bacillus cereus was isolated from all storage conditions, but mostly from products stored at abuse temperature (C) 2000 Academic Press.