title: Investigations on the frequency of norovirus contamination of ready-to-eat food items in Istanbul, Turkey, by using real-time reverse transcription PCR.
abstract: Investigation of norovirus (NoV) contamination of food items is important because many outbreaks occur after consumption of contaminated shellfish, vegetables, fruits, and water. The frequency of NoV contamination in food items has not previously been investigated in Turkey. The aim of this study was to investigate the frequency of human NoV genogroups (G) I and II in ready-to-eat tomatoes, parsley, green onion, lettuce, mixed salads, and cracked wheat balls. RNA was extracted with the RNeasy Mini Kit, and a real-time reverse transcription (RT) PCR assay was performed using primers specific for NoV GI and GII. Among the 525 samples analyzed, NoV GII was detected in 1 green onion sample and 1 tomato sample by both SYBR Green and TaqMan real-time RT-PCR assays; no GI virus was detected. The Enterobactericaeae and Escherichia coli levels in the NoV-positive green onion were 6.56 and 1.28 log CFU/g, and those in the tomato were 5.55 and 1.30 log CFU/g, respectively. No significant difference in the bacterial levels was found between the NoV-positive and NoV-negative samples. This study is the first in which NoV GII was found in ready-to-eat food collected from Istanbul, Turkey; thus, these foods may be considered a risk to human health. Epidemiological studies and measures to prevent NoV infection should be considered.
authors.affiliation: Cevre Industrial Analysis Laboratory, Merkez Mahallesi, Ceylan Sokak, No. 24, Mart Plaza, Kat 2, Kagıthane, Istanbul, Turkey. aysunyilmaz@cevreanaliz.com
authors.forename: Aysun
authors.initials: A
authors.lastname: Yilmaz
authors.forename: Kamil
authors.initials: K
authors.lastname: Bostan
authors.forename: Eda
authors.initials: E
authors.lastname: Altan
authors.forename: Karlo
authors.initials: K
authors.lastname: Muratoglu
authors.forename: Nuri
authors.initials: N
authors.lastname: Turan
authors.forename: Derya
authors.initials: D
authors.lastname: Tan
authors.forename: Christopher
authors.initials: C
authors.lastname: Helps
authors.forename: Huseyin
authors.initials: H
authors.lastname: Yilmaz
mesh_terms: D004755:Enterobacteriaceae / Q000254:growth & development / Q000302:isolation & purification; D004926:Escherichia coli / Q000254:growth & development / Q000302:isolation & purification; D057140:Fast Foods / Q000821:virology*; D005504:Food Analysis / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006801:Humans; D029322:Norovirus / Q000302:isolation & purification*; D011634:Public Health; D012367:RNA, Viral / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D014421:Turkey
chemical_list: D012367:RNA, Viral