Ontario’s Chief Officer of Health has warned the province’s consumers not to eat Siena Brand Prosciutto Cotto cooked ham because it may be contaminated with Listeria monocytogenes. This product would have been sold to consumers after January 11, 2010 and has best before dates of March 8 and March 22, 2010.

Dr. Arlene King issued the warning because the genetic fingerprint of the product is a match to two listeriosis cases in Ontario. Both individuals were hospitalized but have been discharged and are now recovering.

The genetic fingerprint is also a match to a Siena Brand mild cacciatore salami that was recalled in December.

“I want to warn Ontarians not to consume these two products,” she said in a press release. “They both have the exact same genetic fingerprints as two listeriosis cases in Ontario. Those most at risk include pregnant women, the very old, infants, and people with weakened immune systems.”

Listeriosis is caused by the bacterium Listeria monocytogenes, usually transmitted through food. Those highly susceptible are newborns, the elderly, pregnant women, and persons whose immune systems are compromised. In pregnant women, infection can cause preterm delivery, spontaneous abortion, stillbirths and fetal infection

Listeriosis usually manifests as mild flu-like illness. More severe illness may result in meningitis and blood poisoning in newborns and adults. In pregnant women, it can cause fever and abortion.

There has been a higher than-normal rate of listeriosis with 14 already being reported.

There are usually about 40 annually.

Ten of the 12 other cases have 10 different DNA patterns and do not appear to be linked in any way to one another while laboratory results are still pending for the remaining two cases.

All cases involve adults.