Listeria and bacon recall

I was just scanning the news and did a double take.  An Ontario company, Aliments Prince, S.E.C., has just recalled 380,000 lbs of bacon because of possible contamination with Listeria monocytogenes.  That's a lot of bacon!

It seemed to me that this was excessively cautious.  L. monocytogenes should not be found in a food product that has been processed in such a way that the bacteria should not survive, but the organism can occasionally be found in foods that have not been given a listericidal process.  So green leafy vegetables and other raw foods may occasionally contain L. monocytogenes.  The bacteria can be found in many parts of the environment, such as surface water, soil and decaying vegetation, and it's not surprising to find it turning up sometimes in raw foods.

On closer reading, it turns out that the FSIS found a sample of cooked diced bacon from Aliments Prince contained the bacteria.  This is a whole new ball game - the product could be expected to be consumed without further heating and thus could put at risk susceptible consumers.  See my post "Listeria Hysteria" for further information.

The company has done the right thing.  We can't avoid occasional low levels of contamination of raw foods by L. monocytogenes, but something has gone seriously wrong when we find it in cooked foods.  Either the process given was too mild, or, much more likely, the product has been recontaminated post processing.