HIGH HYDROSTATIC PRESSURE EFFECT ON SACCHAROMYCES CEREVISIAE, ESCHERICHIA COLI AND LISTERIA INNOCUA IN PEAR NECTAR

Acid adaptation increased the resistance of Escherichia coli O157:H7 in bok choy (Brassica rapa subsp. chinensis) juice to high-pressure processing

IMPORTANCE

Based on the U.S. Food and Drug Administration regulations, E. coli O157:H7 is a pertinent pathogen in high acid juices that needs to be inactivated during the pasteurization process. The results of this study suggest that the effect of acid adaptation should be considered in the selection of HPP parameters for E. coli O157:H7 inactivation to ensure that pasteurization objectives are achieved.

Optimization of high pressure processing for microbial load reduction in Diospyros kaki 'Fuyu' pulp using response surface methodology

Diospyros kaki L., cv. Fuyu is a non-astringent seasonally available persimmon variety from New Zealand having short shelf life. Most of the current preservation techniques like pasteurization, spray drying etc. use high temperature for microbial inactivation, which results in quality reduction. In the present study, response surface methodology having Box-Behnken design used to explore the consequence of pressure (200-600 MPa), time (5-15 min) and temperature (20-45 °C) for controlling microbial load in fruit pulp. A mathematical model created to envision the responses, and the R² value indicated that the established model proved highly accurate in the prediction of response. The optimization process advocated non-thermal minimal processing of persimmon pulp by high pressure processing at low temperature 20 °C, 400 MPa pressure for 5 min holding time for reducing total plate count and yeast mould count.

High Pressure Processing Treatment of Fresh-Cut Carrots: Effect of Presoaking in Calcium Salts on Quality Parameters

Effect of high pressure (HP) treatment (200–600 MPa; 0–20 min) on quality of fresh-cut carrot slices was evaluated after presoaking in selected calcium salt solutions (1% calcium chloride, 1% calcium lactate, 1% calcium gluconate, and distilled water as control) for one hour. Results showed that calcium chloride (CaCl2) solution pretreatment was most effective for preserving the hardness of carrot slices at 400 and 600 MPa and this treatment also resulted in the least amount of color change in carrots, followed by calcium lactate, gluconate, and control pretreatments. The average sensory evaluation scores during 9 days of refrigerated storage at 4°C in control, CaCl2, calcium lactate, and calcium gluconate presoaking treatments followed by HP treatment were 6.4 ± 0.5, 8.0 ± 0.5, 7.8 ± 0.4, and 7.6 ± 0.3, respectively, on a zero to 9 scale for quality.