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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Food Safety and Intervention Technologies Research » Research » Publications at this Location » Publication #308731
Title: Validation of a pulsed electric field process to pasteurize strawberry puree

Author
item Geveke, David
item AUBUCHON, ISOLDE - American Beverage Marketers
item Zhang, Howard
item Boyd, Glenn
item Sites, Joseph
item BIGLEY, ANDREW - Retired ARS Employee

Submitted to: Journal of Food Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2015
Publication Date: 6/5/2015
Citation: Geveke, D.J., Aubuchon, I., Zhang, H.Q., Boyd, G., Sites, J.E., Bigley, A. 2015. Validation of a pulsed electric field process to pasteurize strawberry puree. Journal of Food Engineering. 166:384-389.

Interpretive Summary: Pulsed electric fields (PEF) pasteurization is a promising nonthermal alternative to traditional thermal pasteurization. However, a major concern expressed by the FDA, regarding the approval of PEF processing, is validating that the food actually receives a sufficient number of electrical pulses. An inexpensive data acquisition method was developed to validate the exact number of the pulses applied during PEF processing. The novel validation method was evaluated in conjunction with developing a PEF process for strawberry puree. The population of E. coli was reduced by 99.99999% in strawberry puree processed in a PEF pilot plant at only 52.5 °C with an electric field strength of 24 kV/cm. The flavor and color of a strawberry beverage made from PEF processed puree fared better than that of a beverage made from thermally processed strawberry puree during the first 5 months of storage. The continuous high-speed data acquisition system, which ran on a laptop, recorded each pulse for validation purposes. The data acquisition system showed the details of every pulse applied for 1 hour for a total of 1.8 million pulses. This research produced a pasteurized strawberry beverage with a superior quality compared to a thermally pasteurized beverage. In addition, a data acquisition system was developed to validate the process that will aid in obtaining FDA approval of the PEF process.

Technical Abstract: An inexpensive data acquisition method was developed to validate the exact number and shape of the pulses applied during pulsed electric fields (PEF) processing. The novel validation method was evaluated in conjunction with developing a pasteurization PEF process for strawberry puree. Both buffered peptone water (BPW) and fresh strawberry puree (pH 2.4) were inoculated with Escherichia coli (ATCC 35218) and processed using a pilot plant PEF system at field strengths of 24.0 – 33.6 kV/cm, outlet temperatures of 45.0 – 57.5 degrees C and a flow rate of 100 l/hr. An accelerated (forced-age) storage study was performed on the quality of a strawberry beverage made from the strawberry puree. A continuous high-speed data acquisition system was developed that recorded every pulse for validation purposes. The populations of E. coli were reduced by 6.5 log in BPW at 30 kV/cm and 57.5 degrees C and 7.3 log in strawberry puree at 24 kV/cm and 52.5 degrees C. The taste and color of strawberry beverage made from PEF processed puree fared better than that of a beverage made from thermally processed strawberry puree during the first 5 months-equivalent of storage. After that, the quality was similar. The data acquisition system captured the details of every pulse applied at a rate of 400 Hz for 1 hour for a total of over 1.4 million pulses. Strawberry puree was pasteurized in a pilot-scale PEF unit. The quality of the PEF pasteurized product was superior to that of the thermally pasteurized product. In addition, a data acquisition system was developed to validate the process which should aid in obtaining FDA approval of the PEF process.