It’s a mystery, how various health agencies decide when to issue public warnings about particular food products.

On Wednesday, Ontario health officials announced they were investigating two cases of listeriosis that appear to be linked to salami recalled from stores in Ontario and Quebec about three months ago.

The salami was sold by Siena Foods based in Toronto and was voluntarily recalled by the manufacturer on Dec. 21, 2009, the Canadian Food Inspection Agency said Wednesday. The best before date on the packaged meat is May 4, 2010.

Last night, CFIA and Siena Foods Ltd. warned the public not to consume certain Siena brand Prosciutto Cotto Cooked Ham below because it may be contaminated with Listeria monocytogenes.

The affected product Siena brand Prosciutto Cotto Cooked Ham, was sold to delicatessens, grocery and speciality food stores in large wholesale packages for further slicing bearing Best Before dates of March 8 and March 22, 2010.

The affected product would have been sold to consumers after January 11, 2010. However, the original brand and/or best before dates may not have been transferred at the deli counters to consumer packages. Persons who may have purchased cooked ham after January 11, 2010 and do not know original brand and code are advised to check with their retailer or supplier to determine if they have the affected product.

So much for traceability.

This recall is based on positive test results for Listeria monocytogenes in product samples and CFIA’s investigation of these findings.

The CFIA is aware of reported listeriosis illness in Ontario and is collaborating with the Province of Ontario Ministry of Health and Long Term Care, the Public Health Agency of Canada and Health Canada to investigate these illnesses. At this time, no confirmed linkage has been made between the subject recalled products and the reported illnesses.

That’s CFIA-speak for ‘we haven’t found the same Listeria in an unopened package. But we found enough links to go public and cover ourselves.’

I hate myself for being able to interpret CFIA-speak.