Research Note: Transfer of Natural and Artificially Inoculated Microorganisms from Orange Fruit to Fresh Juice during Extraction

Abstract

Transfer of natural and inoculated microorganisms from fruit to fresh orange juice was quantified during extraction. The influences of test organisms and inoculation levels on the transfer were also evaluated. About 1.7-2.6% of total aerobic organisms and 2.3-2.6% of aciduric organisms of washed oranges were introduced to the fresh juice during extraction. Approximately 1.3-9.9% of Escherichia coli and 2.7-8.9% ofLactobacillus plantarum were recovered in juice extracted from artificially inoculated fruit. No significant difference (P≥0.05) in transfer was found with the variance of cutter size or strainer tube. Furthermore, the type of test cultures, E. coli or L. plantarum, used for inoculation did not significantly affect the results when an identical broth was used for cell resuspension. In general, microbial levels detected in fresh juice were 90-99% (or 1-2 log) lower than levels found on fruit. © 2001 Academic Press.