Reproducibility study for the detection of Staphylococcal enterotoxins in dairy products between official Italian national laboratories.
Staphylococcal food poisoning is a common foodborne disease caused by the ingestion of staphylococcal enterotoxins (SEs) produced mainly by enterotoxigenic strains of Staphylococcus aureus. To date, 21 SEs and/or enterotoxin-like types have been identified, several of which represent a potential hazard for consumers. To protect consumer health and to reduce the amount of SE-contaminated food entering the market, European Union legislation regulating food safety requires testing for SEs. The Italian National Reference Laboratory organized a ring trial to test technical and analytical proficiency in the national network of official food laboratories. Twenty-four laboratories took part, and each received and analyzed 24 blind dairy samples. Reproducibility of the results from the laboratories was assessed by the Cohen k index, and accuracy (sensitivity and specificity) was evaluated according to the International Organization for Standardization definition (ISO 16140:2003). Trial results revealed partially satisfactory agreement: 254 of 276 possible paired participants (92%) reached a k value >0.60, which is conventionally recognized as satisfactory. Accuracy was deemed satisfactory; 100% sensitivity and 100% specificity were achieved by 22 and 18 of the 24 laboratories, respectively.
Italian National Reference Laboratory for Coagulase-Positive Staphylococci Including Staphylococcus aureus, S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy. manila.bianchi@gmail.com manila.bianchi@izsto.it.
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Bianchi
S. S. Biostatistica Epidemiologia e Analisi del Rischio, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Ingravalle
S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Adriano
Italian National Reference Laboratory for Coagulase-Positive Staphylococci Including Staphylococcus aureus, S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Gallina
S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Gramaglia
S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Zuccon
S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Astegiano
S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Bellio
S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Macori
S. S. Biostatistica Epidemiologia e Analisi del Rischio, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Italian National Reference Laboratory for Coagulase-Positive Staphylococci Including Staphylococcus aureus, S. C. Controllo Alimenti e Igiene delle Produzioni, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Via Bologna 148, 10154 Torino, Italy.
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Decastelli
D000818:Animals; D003611:Dairy Products / Q000032:analysis / Q000382:microbiology*; D004768:Enterotoxins / Q000032:analysis* / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology / Q000592:standards*; D006801:Humans; D007558:Italy; D007753:Laboratories / Q000592:standards*; D015203:Reproducibility of Results; D013202:Staphylococcal Food Poisoning / Q000382:microbiology / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D004768:Enterotoxins