No abstract

Aims:  To study the accumulation of vegetative cells and endospores of Alicyclobacillus, as well as viable aerobic counts during the continuous production of apple juice concentrate. Methods and Results:  Apples were processed for a continuous process running time of 108 h (processing rate 1·8–2·0 t h−1) without clean‐in‐place (CIP) procedures in‐between different batches. Samples from single‐strength apple juice, concentrate after evaporation (±30°Brix), the final product (concentrate pasteurized at 102–104°C for 90 s) and condensate water (by‐product of the juice concentration process) were collected every 12 h. From 12 to 84 h of processing, vegetative Alicyclobacillus counts in single‐strength apple juice increased significantly (P < 0·05) from 1 to 3·15 log10 CFU ml−1. Accumulation patterns of vegetative cells in apple concentrate and the final product were similar from 24 to 84 h of processing, with the respective counts increasing from 0·13 to 1·63 and 0·01 to 1·69 log10 CFU ml−1. The highest Alicyclobacillus endospore counts in single‐strength juice, concentrate and the final product was at 84 h of processing with 1·32, 1·59 and 1·64 log10 CFU ml−1, respectively. Conclusions:  Alicyclobacillus vegetative cells and endospores accumulate in fruit concentrates during a continuous process running time of 108 h. Significance and Impact of the Study:  In conjunction with good manufacturing practices, fruit concentrate manufactures can minimize Alicyclobacillus accumulation in fruit concentrates by limiting the continuous process running time between clean‐ups to under 84 h.

Alicyclobacillus and viable aerobic counts were monitored at nine different production stages of pear concentrate, with the functioning of either a recirculating or a one-pass flume water system. Significantly (P \ 0.05) higher levels of Alicyclobacillus were detected in the final pasteurized product (102-104°C for 90 s) when the recirculating flume water system was operational.