title: Detection of Food Hazards in Foods: Comparison of Real Time Polymerase Chain Reaction and Cultural Methods.
abstract: Foodstuffs should not contain microorganisms or their toxins or metabolites in quantities suggesting an unacceptable risk for human health. The detection of food hazards in foods is performed by several tests that produce results dependent on the analytical method used: an analytical reference method, defined as standard, is associated with each microbiological criterion laid down in Regulation 2073/2005/EC, but, analytical methods other than the reference ones, in particular more rapid methods, could be used. Combined screening methods performed by real time-polymerase chain reaction (RT-PCR) are currently validated as alternative methods according to the ISO 16140:2003 and certified by theAssociation Française de Normalisation. However, the positive results obtained with these alternative methods, the investigated molecular relations that resulted positive have to be confirmed with cultural methods using the same enrichment media in which the molecular screening was performed. Since it is necessary to assess if these testing schemes provide equivalent guarantees of food safety, the aim of this retrospective study is to analyse the data collected, from 2012 to 2014 by Emilia Romagna Region in the field ofPiano Regionale Alimenti(Food Regional Plan) during official controls monitoring food samples of animal and other than animal origin. Records performed by combined methods of molecular screening ofSalmonellaspp.,Listeria monocytogenesand thermophilicCampylobacterand cultural confirmation results were gathered together and the results were compared in order to assess the sensitivity of the methods. A total of 10,604 food samples were considered in this study: the comparison of the data revealed that the RT-PCR method detectedSalmonella, L. monocytogenes, and thermophilicCampylobacterin 2.18, 3.85 and 3.73% of the samples, respectively, whereas by using cultural method these pathogens were isolated in 0.43, 1.57 and 1.57% of samples, respectively. In spite of the use of the same enrichment broth, the RT-PCR method disclosed a percentage of positive samples that was negative to cultural examination ranging between 20 and 43%, with a PCR/culture ratio between 2.37 to 5.00. In conclusion, the results of this study pose a doubt about the sensitivity of the official cultural methods regarding the isolation of the three investigated foodborne pathogens. Moreover this study may be a useful tool for veterinary authorities to assess appropriate sampling plans to control the risk relating to the consumption of contaminated foods.
authors: Institute for Experimental Veterinary Medicine of Lombardy and Emilia Romagna , Brescia.
authors: Paolo
authors: P
authors: Bonilauri
authors: Institute for Experimental Veterinary Medicine of Lombardy and Emilia Romagna , Brescia.
authors: Lia
authors: L
authors: Bardasi
authors: Institute for Experimental Veterinary Medicine of Lombardy and Emilia Romagna , Brescia.
authors: Roberto
authors: R
authors: Leonelli
authors: Institute for Experimental Veterinary Medicine of Lombardy and Emilia Romagna , Brescia.
authors: Mattia
authors: M
authors: Ramini
authors: Institute for Experimental Veterinary Medicine of Lombardy and Emilia Romagna , Brescia.
authors: Andrea
authors: A
authors: Luppi
authors: Department of Veterinary Sciences, Alma Mater Studiorum-University of Bologna , Bologna, Italy.
authors: Federica
authors: F
authors: Giacometti
authors: Institute for Experimental Veterinary Medicine of Lombardy and Emilia Romagna , Brescia.
authors: Giuseppe
authors: G
authors: Merialdi
keywords: Analytical sensitivity; Cultural methods; Food matrices; Real time PCR