Listeria!!!

I have now been baking sourdough for 12 months and starting to feel comfortable with it. To refine my techniques I did a course at the Red Beard Bakery in Trentham, Victoria. It was a good course and I was able to master shaping (hurrah) and find out where to access some really good flour. Like many of my sourdough companions here, I keep my starter in the fridge when it is not being used. On the course I was warned that doing this risks developing listeria in your starter. I have tried to find more information about this with no success. I am still keeping my starter in the fridge and feeding weekly but am nervous that I am about to poison the whole family! Does anyone out there have any information or experience, as I would be curious to know more? 

P.S. Thanks for a great site, have managed to largely teach myself to make some damn fine bread... and loving it.

7 comments

I have never heard this about starter, so it's news to me. My starter is now over two years old and I have kept it in the refrigerator for most of that time feeding once a week. No problems here!

Maybe find a new place for lessons.  Or, better, make Red Beard explain the comment and post it here.

Have not managed to kill anyone yet with my starter.  I don't think you have to worry about it.  Maybe they were talking about if you never refresh your starter and keep it in the refrigerator for like 6 months?  Anyway, it is common practice to keep it in the refrigerator when not using and we can't all be wrong about that.

First of all I would like to thank you for posting this, I had heard that the Trentham guys were discouraging people from storing their starters in the fridge and wondered why. I cannot answer the question exactly I agree with Fred that they really ought to explain their position. However I can offer facts and my interpretations: Lysteria is a highly prevalent water borne bacteria, like most bacterias it thrives between about 20-30, slows down dramatically under 4 and dies over 70 (degrees celsius in all cases). Lysteria's prevalence is very high and is the reason for the discouragement of pregnant women eating room temperature, high protein, high water content foods (soft cheeses, salamis etc) Here is my interpretative bit, the only reason I can see for suggesting that the fridge will increase the risk is that this is where most of the food traditionally suspicious in terms of Lysteria are kept. I keep my starter in the fridge for the ip to a week period between bakes, on a closed preserving jar (sprung lid, rubber seal), I believe it has less chance "catching" Lysteria in this environment that when I have it on the bench in my baking bowl developing for 48hrs with a loose cover (lysteria will be more active in this environment and can be present in any moisture including the air). We know in fact that we keep our starters in the fridge to slow down the bacteria growth, giving us the convenience of a healthy starter with less frequent use. With regards to the safety of ourselves and those we feed: Lysteria dies at 70degreesC, the centre of your loaf will reach close to 100degreesC for about 1/4 of the baking time in order to be a baked loaf of bread with a stable crumb. This is the same basis for the recommendations to reheat meats to at least 70C that the FSDA tell us, it kills any present dangerous bacteria. Another point of note, everyone has superstitions (even chefs and bakers) if something doesn't make sense or isn't clear ask "WHY?" My personal breadmaking serstition is to always use a pancheon or tian (cone shaped) pottery bowl to mix my dough, it is traditional and just seems to develop better! Heheh I hope my answer helps a little.

Thanks for such an informative post Sara.

:) Maree

Thank you so much for all your replies, especially Sara's thoughts on the subject. I do feel reassured and like your analytical approach. Thanks again.

Well Listeria is everywhere.  Yes, it causes problems, as does E. coli, eboli, cholera, and a very large number of other infectious microorganism.  To name this particular organism, without any specifics, is silly from anyone's point of view.  Either the poster, or the source, ought to take time to post a follow up as to why this is important to bakers.  Or, forget it.