Capillary Electrophoresis-Based Detection for Foodborne Enteroviruses in Vegetable Samples

Abstract

Foodborne enteroviruses such as norovirus, rotavirus and astrovirus can cause gastroenteritis in children under the age of five and infants. In this paper, a novel and ultrasensitive method, combining reverse transcription polymerase chain reaction (RT-PCR) with capillary electrophoresis laser-induced fluorescence (CE-LIF), is proposed to detect three viruses in vegetable samples. The viruses, including norovirus, rotavirus and astrovirus in vegetables, were eluted using glycine buffer (pH 9.5), and concentrated by 15 % polyethylene glycol 6000 (PEG 6000). The primers, targeting the specific and conservative sequences of nucleic acids of the viruses, were synthesized and used in RT-PCR reaction. The amplification products were labeled with highly sensitive SYBR Gold, then separated by capillary electrophoresis and detected by a laser-induced fluorescence detector within 16 min. The intraday and interday relative standard deviation of migration time for the DNA Marker was in the range of 1.09–1.30 and 1.77–2.60 %, respectively, while the detection limits of the three viruses were as low as 1.33 × 10² copies mL⁻¹ for norovirus, 1.86 × 10² copies mL⁻¹ for rotavirus, and 1.40 × 10² copies mL⁻¹ for astrovirus. Meanwhile, the results of homology analysis and specificity experiments showed that the method had good specificity. A fried pickled mustard tuber tested positive for norovirus by the proposed method in an outbreak which happened recently in Chengdu. This protocol demonstrated the possibility for rapid, sensitive and specific detection of foodborne enteric viruses in vegetable samples.