9 replies to this topic

[lbanaszak]

Anyone ever experienced positive Listeria welshimeri results on finished product from the beginning of the run, but not the middle or end? The same lot of veggies were used throughout all 6 mixes. We are at a loss and pulling our hair out over here trying to figure this out! Thanks in Advance for any insight.....

 

 

 

[Scampi]

According to this: Listeria welshimeri is a species of bacteria. It is a Gram-positive, facultatively anaerobic, motile, non-spore-forming bacillus. It is non-pathogenic and non-hemolytic. It was isolated from decayed vegetation in the United States by H. J.

 

Are you sure the concentrations on the wash were correct at start up?  Enough agitation etc?

 

If the produce wash wasn't functioning when veg introduced first, seeing it at the beginning only would make sense

[lbanaszak]

According to this: Listeria welshimeri is a species of bacteria. It is a Gram-positive, facultatively anaerobic, motile, non-spore-forming bacillus. It is non-pathogenic and non-hemolytic. It was isolated from decayed vegetation in the United States by H. J.

 

Are you sure the concentrations on the wash were correct at start up?  Enough agitation etc?

 

If the produce wash wasn't functioning when veg introduced first, seeing it at the beginning only would make sense

 Hmmm, interesting we get all veggies IQF, Ill have to investigate with the supplier. Thanks for the input. 

[Charles.C]

Anyone ever experienced positive Listeria welshimeri results on finished product from the beginning of the run, but not the middle or end? 

 

The same lot of veggies were used throughout all 6 mixes. 

 

We are at a loss and pulling our hair out over here trying to figure this out! 

 

Thanks in Advance for any insight.....

 

I'm confused as to the Process/Run.

 

What is being mixed and how ?

[Scampi]

Charles, they get in IQF veg and blend them...............first production run using the same batches of veg has a positive hit

[Charles.C]

Charles, they get in IQF veg and blend them...............first production run using the same batches of veg has a positive hit

 

An unlucky but presumably FS meaningless fluke unless repeatable under identical conditions.

[lbanaszak]

An unlucky but presumably FS meaningless fluke unless repeatable under identical conditions.

I was thinking this, We sent out multiple samples to be tested where only samples from the beginning of the production run tested positive. 

[Charles.C]

I was thinking this, We sent out multiple samples to be tested where only samples from the beginning of the production run tested positive. 

 

So Is it just a solid/solid mixing or were liquids involved as per Scampi ?

 

So how many (each run-identical?) items were being (each run-continuously?) blended under (each run-identical?) conditions ?

 

(my [obvious] suspicion is that one item is  being inputted in (somehow) different way at the beginning).

 

It might have been useful to test the source lot(s) used for each input for Listeria species.

 

How was the sampling done ?

[Ken Bookmyer]

There was a study on sliced meat (years ago and I can't cite source) where they determined that throwing away the first couple of slices was an important control. if there was any bacteria on the surface of the equipment it was wiped off by the meal and subsequent slices tested lower. Have you checked your surfaces immediately before running? Maybe it's environmental? 

[Karenconstable]

Listeria is notorious for making hard-to-remove biofilms in nooks and crannies of equipment.  Rust spots on equipment are also said to be a source of Listeria. 

 

I agree with Ken (above), I think you should consider environmental sources. 

 

There's a good possibility that the product is picking up the Listeria from the (mixing?) equipment; this would explain why you only see it at the beginning of the runs. 

 

Can you do some swabbing of the equipment and surrounds?