Rapid detection method for hepatitis A virus from lettuce by a combination of filtration and integrated cell culture-real-time reverse transcription PCR

J Food Prot. 2011 Oct;74(10):1756-61. doi: 10.4315/0362-028X.JFP-11-155.

Abstract

We have developed a rapid and simple method for filtration using a positively charged membrane to concentrate hepatitis A virus (HAV) from lettuce and an integrated cell culture-real-time reverse transcription PCR (ICC-real-time RT-PCR) to detect infectious HAV. The most suitable buffer for HAV concentration by filtration was 100 mM Tris-HCl, 50 mM glycine (pH 9.5). Filtration using the NanoCeram matrix was compared with polyethylene glycol precipitation for viral concentration from lettuce inoculated with 6 log RNA copies of HAV. The recovery rate of filtration was statistically higher than that of polyethylene glycol precipitation (47.3 versus 24.9%, respectively). The sensitivity of ICC-real-time RT-PCR for detection of infectious HAV was determined by inoculation of FRhK-4 cells with HAV (4 log to 0 log RNA copies). ICC-real-time RT-PCR detected infectious HAV on average 5 days earlier than cytopathic effects at all inoculation levels. HAV recovered from lettuce (approximately 3 log RNA copies) was also analyzed with ICC-real-time RT-PCR. Infectious HAV was detected within 2 days postinfection by ICC-real-time RT-PCR, whereas cytopathic effects were not observed until 7 days postinfection. Coupled with a virus concentration and purification system using a positively charged membrane, ICC-real-time RT-PCR has the potential to become a novel and rapid method for the detection of infectious HAV in vegetables.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Culture Techniques
  • Colony Count, Microbial
  • Consumer Product Safety
  • Filtration / methods*
  • Food Contamination / analysis*
  • Food Microbiology
  • Hepatitis A virus / isolation & purification*
  • Humans
  • Lactuca / virology*
  • RNA, Viral / analysis
  • Reproducibility of Results
  • Reverse Transcriptase Polymerase Chain Reaction / methods*
  • Sensitivity and Specificity
  • Time Factors
  • Virulence

Substances

  • RNA, Viral