Evaluation and Improvement of Methods to Recover and Detect Hepatitis A Virus and an Indicator Virus (F+ RNA Coliphage MS2) in Representative Foods Associated witrh Viral Foodborne Outbreaks
Seventy-six million illnesses and 5,200 deaths are estimated to occur each year in the United States associated with foodborne transmission of microbial pathogens. Viral pathogens cause an estimated 7 out of 10 foodborne illnesses of known etiology. Improved methods to recover and detect viruses in foods may reduce morbidity and mortality associated with foodborne disease by identifying routes of viral transmission and by improving source tracking for foodborne outbreaks. Methods were developed and evaluated for recovery and detection of an enteric human virus. Hepatitis A virus (HAV), and an indicator virus, F+ RNA coliphage MS2(MS2), in foods commonly associated with viral foodborne outbreaks. In this study, HAV was inoculated into tomato sauce, strawberries, and oysters, then recovered by either an acid-adsorption-elution-concentration (AA/E) method or an alkaline-elution-concentration method. Viruses were detected and enumerated by cell infectivity or by molecular methods. For molecular detection and quantification, viral RNA was extracted and amplified by conventional, nested, or realtime RT-PCR. The results of this study indicate that the AA/E method, initially used to recover low levels of enteric viruses from shellfish, may also be applied for the recovery of viruses from other complex foods, such as produce and sauces. Additionally, produce and sauces contain fewer enzymatic inhibitors to molecular detection than oysters. Because of this, larger produce and sauce samples can be analyzed by molecular detection methods, leading to possibly lower virus detection levels and greater assay sensitivity in these foods.Master of Science in Public Healt
