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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 #305807
Title: Atmospheric cold plasma inactivation of Aerobic Microorganisms on blueberries and effects on quality attributes

Author
item Lacombe, Alison
item Niemira, Brendan
item Gurtler, Joshua
item Fan, Xuetong
item Sites, Joseph
item Boyd, Glenn
item CHEN, HAIQIANG - University Of Delaware

Submitted to: Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2014
Publication Date: 4/1/2015
Citation: Lacombe, A.C., Niemira, B.A., Gurtler, J., Fan, X., Sites, J.E., Boyd, G., Chen, H. 2015. Atmospheric cold plasma inactivation of Aerobic Microorganisms on blueberries and effects on quality attributes. Food Microbiology. 46:479-484.

Interpretive Summary: Cold plasma (CP) is a novel nonthermal technology, potentially useful in food processing settings. In practice, it can be considered a form of energized gas. Blueberries were treated with atmospheric CP for 0, 15, 30, 45, 60, 90, or 120s at a working distance of 7.5 cm with a mixture of 4 cubic feet/minute (cfm) of CP jet and 7 cfm of ambient air. Blueberries were sampled for total aerobic plate count (APC) and yeast/molds immediately after treatment and at 1, 2, and 7 days. Blueberries were also analyzed for compression firmness, surface color, and total anthocyanin (coloration pigments) immediately after each treatment. All treatments with CP significantly reduced APC immediately after exposure, with reductions ranging from 84 – 97% compared to the control, depending on the treatment time. These reductions persisted throughout 7 days of storage at 4 deg C, with APC counts 97 – 99% less than the control at the final sampling. Treatments longer than 60s resulted in significant reductions in firmness and a reduction in total anthocyanins. The surface color measurements were significantly impacted after 45 s. CP can inactivate microorganisms on blueberries and could be optimized to improve the safety and quality of produce.

Technical Abstract: Cold plasma (CP) is a novel nonthermal technology, potentially useful in food processing settings. Berries were treated with atmospheric CP for 0, 15, 30, 45, 60, 90, or 120s at a working distance of 7.5 cm with a mixture of 4 cubic feet/minute (cfm) of CP jet and 7 cfm of ambient air. Blueberries were sampled for total aerobic plate count (APC) and yeast/molds immediately after treatment and at 1, 2, and 7 days. Blueberries were also analyzed for compression firmness, surface color, and total anthocyanins immediately after each treatment. All treatments with CP significantly (P < 0.05) reduced APC immediately after exposure, with reductions ranging from 0.8 – 1.6 log CFU/g compared to the control, depending on the treatment time. These reductions persisted throughout 7 days of storage at 4 deg C, with APC counts 1.5 – 2.0 log CFU/g less than the control at the final sampling. Treatments longer than 60s resulted in significant reductions in firmness and a reduction in total anthocyanins. The surface color measurements were significantly impacted after 120s for the L and a values and 45 s for the b values. CP can inactivate microorganisms on blueberries and could be optimized to improve the safety and quality of produce.