Evaluation of the Microbiological Quality of IQF Processed Maine Wild Blueberries: An "In Plant Study"

This study examined the influence of processing on microbiological characteristics of individually quick frozen (IQF) wild blueberries. Field blueberries had a mean initial Aerobic Plate Count (APC) of 4.39 ± 1.02 log CFU/g. Current processing methods reduced the APC of final product to a mean of 1.97 ± 1.53 log CFU/g, yielding an average reduction of 2.42 log. Testing showed 65.7% (71 of 108) of samples positive for coliforms and only 36.1% (39 of 108) positive for Esch-erichia coli. All 24 frozen samples tested negative for E. coli, one tested positive for coliforms. Staphylococcus spp. were not detected in samples at any point in the processing. This study indicates that the combination of various microbial reduction methods used in many IQF processing plants (fresh water wash, chlorine spray, and freezing) are effective at reducing microbial load.