An Innovative Enzyme-Based Time-Temperature
Integrator for Assessment of Pathogen Reduction
by Combined Heat and High Hydrostatic
Pressure Treatment of Juice

Problem Addressed

Ensuring food safety, reducing processing costs and increasing customer satisfaction are some of the most important considerations for food processors. The increasing demand of safe fresh-like foods along with the increase in energy costs has put food processors in a dilemma. While reducing thermal treatment of foods increases the retention of fresh-like attributes and reduces energy consumption, it increases the likelihood of pathogen survival. Alternative non-thermal processes such as high hydrostatic pressure (HHP) and combinations of thermal and non-thermal technologies have been developed in recent years. Combing thermal and HHP processing has the potential of increasing the quality of acid foods like apple juice, and even some low acid foods where HHP alone is insufficient to destroy certain pathogens and spores. Implementation of the proposed sensor technology would result in increased product quality while ensuring safety and increasing the potential for export.

Goal

To develop an enzyme-based time-temperature integrator (TTI) sensor for combined thermal and high hydrostatic pressure processing of fruit juices.

Implications

Procedures

1. TTI fabrication and testing.
2. Determination of the Kinetics of Microorganism Reduction and Enzyme Inactivation.
3. Data analysis of variance to determine significant differences among means of microbial number and enzyme activity for treatments and to calculate confidence intervals.

Techniques and Technologies Developed

• Platinization conditions of platinum electrodes were improved to produce mechanically-stable porous platinum deposits.
• For the purpose of increasing biosensor sensitivity, researchers found that enzyme immobilization films must be very thin (20-40 nm) in order to cover the surface of the platinum pores without filling them, allowing effective use of the increase in surface area produced by electrode platinization, which translates in larger current response of the biosensor.
• In contrast to TTIs, it is necessary that enzyme biosensors for food analysis be very stable and that the enzyme activity remains unchanged for a long period of time.

Patents or License Received (A provisional patent was applied for)

Reyes-De-Corcuera JI, Cavalieri RP, Powers JR. “Enzyme-Based Amperometric Time-Temperature Integrator Method And Device.” Provisional patent 60/524,251 (11/20/03)

Publications/Journal Articles From Project

Reyes De Corcuera J.I., R.P.Cavalieri and J.R. Powers. 2005. “Improved Platinization Conditions Produce A 60-Fold Increase In Sensitivity Of Amperometric Biosensors Using Glucose Oxidase Immobilized In Poly-O-Phenylenediamine.” Journal of Electroanalytical Chemistry 575 (2): 229-241.

Reyes De Corcuera J.I., R.P. Cavalieri, J.R. Powers. 2004. “Simultaneous Determination Of Film Permeability to H2O2 and Substrate Surface Area Coverage Of Overoxidized Polypyrrole.” Synthetic Metals 142 (1-3): 71-79.

Reyes De Corcuera, J.I., Cavalieri. 2003. Biosensors. In: Encyclopedia of Agricultural and Food Engineering. Heldman, D. Editor. Marcel Dekker, Inc. pp 119-123 (Available on-line at http.www.Dekker.com)

Reyes De Corcuera, J. I., R. P. Cavalieri, J. R. Powers, and J. Tang. 2004. “Amperometric Enzyme Biosensor Optimization Using Mathematical Modeling.” In Proceedings of the 2004 ASAE / Csae Annual International Meeting, American Society of Agricultural Engineers, Ottawa, Ontario.

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