okay , thank you guys .
But how is that possible ?
Example: we are running whipping cream, one of the tub time : 13:00 tested positive for listeria seeligeri , and another tub with the cream collected from the line 13:03 has listeria Mono .
How possible is that . The samples have been tested for 125 g .
JFI, this is a 1993 quote -
Three hundred samples of pastry from 100 different suppliers in western France, including butter-cream, whipped dairy cream and custard filled cakes from each supplier, were collected and tested for the occurence of Listeria spp. in 25 g samples.
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Listeria spp. were detected in 21.7% of the samples: Listeria monocytogenes in 13.7%, Listeria innocua in 10% and Listeria seeligeri in 2.3%.
Thirteen samples were contaminated with two species simultaneously.
The frequency of contaminated samples was not related to the composition of the pastry filling used, but it seemed to increase with the number of aerobic contaminant microorganisms in the dairy cream-based samples.
The contamination rate was dependent on the place of manufacture.
The numbers of Listeria spp. and Listeria monocytogenes were estimated on positive samples at the 25 g level as follows: < 0.3/g, Listeria spp. in 47 samples, L. monocytogenes in 27; 0.3–30/g, Listeria spp. in 13, L. monocytogenes in nine; 30–300/g, L, monocytogenes in one; 300–3000/g; L. monocytogenes in three; 700 000/g, L. monocytogenes in one
Also see this -
Diversity of Listeria Species in Urban and Natural Environments,2012.pdf 1.39MB
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Do you have an EMP running for Listeria ?
PS - Probably not relevant to yr situation but I also noticed this summary comment in a Greek (2015) survey -
Out of all food categories examined, the presence of L.monocytogenes was the highest in desserts with dairy cream and ice cream (22.7% and 26%, respectively), both of which are predominantly made with whipped cream or with pastry cream both of which involve much handling throughout the final formulation process.
Another factor is the omnipresence of uncooked eggs throughout kitchen working stations since the pasteurized liquid/powdered egg option is not favored. This fact, escalated by the occasional addition of raw eggs in the final preparatory stages, leads to cross-contamination of RTE desserts and ice cream.
Kotzekidou [13] reported a high prevalence rate of 20% in desserts with dairy cream and a 17.7% in desserts [27] in studies in Northern Greece.
L.mono and Salmonella spp in RTE Foods,2015.pdf 437.01KB
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