No abstract

The Probelia™Salmonella sp. PCR amplification and detection kits (Sanofi Diagnostics Pasteur, Marnes La Coquette, France) were evaluated for the rapid and specific detection of Salmonella agona artificially inoculated into skim milk powder and ricotta cheese. The Probelia™ results were compared with those obtained using the Australian Standard Method. Using a pure culture of Salm. agona, the detection limit of Probelia™ was between 8 and 79 cfu ml−1, equivalent to 0·2–2 cfu per PCR reaction. Detection of Salm. agona inoculated in skim milk powder (at 5–10 cfu g−1, stored at 5, 15 or 25 °C) and ricotta cheese (at 1–2, 10–20 and 100–200 cfu per 25 g) was effected by using non‐selective enrichment prior to the PCR determinations. For all of the 40 milk powder samples and 12 ricotta cheese samples, the Probelia™ results were consistent with those using the Australian Standard Method. Using Probelia™, Salmonella was detected to genus level in the dairy products within 24–28 h, whereas the cultural technique required 3–4 d for presumptive positive isolates and further time for confirmation.