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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Residue Chemistry and Predictive Microbiology Research » Research » Publications at this Location » Publication #315690

Research Project: DEVELOPMENT OF PREDICTIVE MICROBIAL MODELS FOR FOOD SAFETY AND THEIR ASSOCIATED USE IN INTERNATIONAL MICROBIAL DATABASES

Location: Residue Chemistry and Predictive Microbiology Research

Title: Inactivation of Toxoplasma gondii on blueberries using low dose irradiation without affecting quality

Author
item Lacombe, Alison
item Breard, Anna - University Of Maine
item Hwang, Cheng-an - Andy
item Fan, Xuetong
item Huang, Lihan
item Yoo, Byong
item Niemira, Brendan
item Gurtler, Joshua
item Wu, Vivian - University Of Maine

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2015
Publication Date: 7/25/2015
Citation: Lacombe, A.C., Breard, A., Hwang, C., Fan, X., Huang, L., Yoo, B.K., Niemira, B.A., Gurtler, J., Wu, V. 2015. Inactivation of Toxoplasma gondii on blueberries using low dose irradiation without affecting quality. Meeting Abstract. IAFP Annual Meeting. Portland, Oregon. July 25-28, 2015. Volume 1, Page 1.

Interpretive Summary:

Technical Abstract: Toxoplasma gondii is the most common parasite that contaminates produce. However as more cases of T. gondii contamination are being linked to produce, current washing steps in produce processing may not be effective or suitable for some varieties of produce. The objective of this study was to evaluate the effect of low-dose irradiation on inactivating T. gondii oocysts on blueberries. Blueberries (10 g) inoculated with T. gondii (5 log oocysts/g) were exposed to an absorbed dose of 0 (control), 0.2, 0.4 or 0.6 kGy at 4 degrees Celsius. A self-contained Lockheed Corporation 137CS gamma radiation source at a dose rate of 0.075 kGy/min was utilized. After treatment, oocysts were recovered from berries. Human foreskin fibroblast (HFF) cells were maintained as monolayers in a 96-well microplate, exposed to excysted T. gondii recovered from berries, and incubated for 7 days. The viability of HFF cells was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay. In addition, blueberries were analyzed for compression firmness, surface color, and total anthocyanins immediately after each treatment. HFF cells inoculated with oocysts recovered from the 0.6 kGy treated berries retained viability at 93% compared to the control, indicating that treated oocysts were less infectious to HFF cells. The result showed that gamma radiation significantly (P < 0.05) inactivated T. gondii oocysts on blueberries. Quality analysis showed that there was no significant change in texture, anthocyanins, or color in berries after the irradiation treatment. Findings of this study indicated that low-dose irradiation is a potential intervention measure for controlling T. gondii contamination on blueberries without affecting product quality.