Abstract
Salmonella remains a major public health concern worldwide. Microbiological methods are the gold standard for Salmonella detection. These methods are highly specific, but their sensitivity is variable. Moreover, they are lengthy, labour intensive and not always consistent with the speed of food manufacturing processes. Thus, in the food industry, there is the need for more rapid, sensitive and accurate detection methods. The purpose of this study is to describe a Salmonella-monitoring scheme in different food processing plants based on a screening approach by a commercial real-time polymerase chain reaction (PCR) kit and subsequent confirmation of positive molecular results by the reference microbiological method. This scheme was tested on a total of 4,693 samples, 90 of which were positive with the real-time PCR screening; 52 of the positive samples were eventually confirmed by the microbiological method. The real-time PCR kit was tested in comparison to the microbiological method in order to evaluate its performances and drawbacks. The comparison between cycle threshold (Ct) values of real-time PCR and the microbiological results (Wilcoxon rank sum test) showed a statistically significant difference between the Ct values of bacteriological positive and bacteriological negative samples (p value, <0.05). Furthermore, receiver operating characteristic curve analysis was used to identify the Ct value ensuring the lowest level of misclassification between Salmonella-positive and negative samples. The present study confirms that the real-time PCR kit tested could be used as a screening tool, leading to a rapid and sensitive identification of Salmonella and confining bacteriological confirmation to samples previously identified as positive.
Similar content being viewed by others
References
Abubakar I, Irvine L, Aldus CF, Wyatt GM, Fordham R, Schelenz S, Shepstone L, Howe A, Peck M, Hunter PR (2007) Health Technol Assess 11(36):1–216
Alvseike O, Vardund T, Lindstedt B, Heir E, Eriksson E, Kapperud G (2004) Epidemiol Infect 132(2):253–261
Anonymous (2002) Microbiology of food and animal feeding stuffs—horizontal method for the detection of Salmonella (EN ISO 6579:2002). International Organization for Standardization, Geneva
Bohaychuk V, Gensler GE, King RK, Wu JT, McMullen LM (2005) J Food Prot 68:2637–2647
Cenciarini-Borde C, Courtois S, La Scola B (2009) Future Microbiol 4(1):45–64
Croci L, Delibato E, Volpe G, De Medici D, Palleschi G (2004) Appl Environ Microbiol 70:1393–1396
Delibato E, Fiore A, Anniballi F, Auricchio B, Filetici E, Orefice L, Losio MN, De Medici D (2011) New Microbiol 34:299–306
European Food Safety Authority (2010) The Community Summary Report on trends and sources of zoonoses, zoonotic agents and food-borne outbreaks in the European Union in 2008. EFSA J 1496:1–410
Ferretti R, Mannazzu I, Cocolin L, Comi G, Clementi F (2001) Appl Environ Microbiol 67:977–978
Fratamico PM (2003) Mol Cell Probes 17:215–221
Funk J (2003) J Swine Health Prod 11:87–90
Girones R, Ferrús MA, Alonso JL, Rodriguez-Manzano J, Calgua B, Corrêa Ade A, Hundesa A, Carratala A, Bofill-Mas S (2010) Wat Res 44(15):4325–4339
Havelaar AH, Brul S, de Jong A, de Jonge R, Zwietering MH, Ter Kuile BH (2010) Int J Food Microbiol 139(S1):S79–S94
Hopkins KL, Peters TM, Lawson AJ, Owen RJ (2009) Diagn Microbiol Infect Dis 64:452–454
Dohoo I, Martin W, Stryhn H (2007) Veterinary epidemiologic research, 2nd edn. VER, Inc., Charlottetown, pp 104–106
Jasson V, Jacxsens L, Luning P, Rajkovic A, Uyttendaele M (2010) Food Microbiol 27:710–730
Jokinen C, Edge TA, Ho S, Koning W, Laing C, Mauro W, Medeiros D, Miller J, Robertson W, Taboada E, Thomas JE, Topp E, Ziebell K, Gannon VP (2011) Wat Res 45:1247–1257
Kawasaki S, Fratamico PM, Horikoshi N, Okada Y, Takeshita K, Sameshima T, Kawamoto S (2010) Food Path Dis 7:549–554
Kusumaningrum HD, Riboldi G, Hazeleger WC, Beumer RR (2003) Int J Food Microbiol 85:227–236
Lukinmaa S, Nakari UM, Eklund M, Siitonen A (2004) APMIS 112:908–929
Mackay IM (2004) Clin Microb Infect 10:190–212
Mafu AA, Pitre M, Sirois S (2009) J Food Prot 726:1310–1314
Malkawi HI, Gharaibeh R (2003) J Basic Microbiol 43(4):328–336
Malorny B, Mäde D, Teufel P, Berghof-Jäger C, Huber I, Anderson A, Helmuth R (2007) Int J Food Microbiol 117:211–218
McCabe EM, Burgess CM, O’Regan E, McGuinness S, Barry T, Fanning S, Duffy G (2011) Food Microbiol 28:447–456
Naravaneni R, Jamil K (2005) J Med Microbiol 54:51–54
Nde CW, Fakhr MK, Doetkott C, Logue CM (2008) J Food Protect 71:386–391
Newell DG, Koopmans M, Verhoef L, Duizer E, Aidara-Kane A, Sprong H, Opsteegh M, Langelaar M, Threfall J, Scheutz F, van der Giessen J, Kruse H (2010) Int J Food Microbiol 30(139):S1–S3
Wilkins W, Rajic A, Parker S, Waddell L, Sanchez J, Sargeant J, Waldner C (2010) Zoonoses Public Health 57:121–134
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Lettini, A.A., Barco, L., Mancin, M. et al. A Pilot Study for Identification of Salmonella in Food Processing Plants by Real-Time PCR Screening. Food Anal. Methods 5, 988–994 (2012). https://doi.org/10.1007/s12161-011-9352-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12161-011-9352-8