6 replies to this topic

[kfromNE]

Looking for articles about testing lactic acid bacteria (LAB) testing and shelf-life. Specifically with hot filled soups. 

 

Anything including if LAB is a good indicator for shelf life testing for packaged soups. 

Edited by kfromNE, 27 May 2025 - 07:59 PM.

[Killian]

I jumped at this at this topic a little because I've read a lot about LAB, but unfortunately not in the soup-sphere  . But the first article I found on the topic seemed to consider LAB as serving the purpose of extending shelf life by outcompeting worse microbes (similar to what they do in other fermented food stuffs). I figured I'd post it while we wait for the real experts to weigh in!

Attached Files

•  soup-microbiome-white-paper_dp_8119.pdf   7.4MB   5 downloads

[kfromNE]

Thanks. If you have any general articles about LAB and shelf life - that would be great too. 

[GMO]

A question... why? 

 

1. Are you looking to add them in to extend shelf life? 

2. Or test for them as an indicator of shelf life failure? 

 

If it's 1, why not use heat instead?  If will change the flavour over time and possibly cause undesirable changes.  If it's 2 why is your heat processes not killing it off and why not use TVCs as indicators and pseudomonas spp. as likely spoilage indicators?

[AZuzack]

Here's an article on LAB in Soup.  

https://www.eurofins...od-ingredients/

 

This was a nice overview of spoilage organisms and which types of products they impact but it did not directly address soups.  

https://fri.wisc.edu...oilage_7_07.pdf

 

I think a part of the problem with soups is that the compositions vary widely.  A cream soup is very different from a meaty chili or stew.  Then there's salt content, packaging type, shelf stable vs refrigerated.  

 

If you cannot find a relevant published limit, you can still study it (test for it to see what it does or does not do in your product).  Or for unexpectedly high TPC/APC or AnPCs, you can request additional tests that include other organisms not originally tested.  

 

As GMO stated, unless there's an issue with the heating/cooking step of your process, there shouldn't be any LAB in your product when it's being filled.  Now if you added a non-cooked ingredient at that stage or have something in your environment contaminating the packaging, then maybe.  

[kfromNE]

A question... why? 

 

1. Are you looking to add them in to extend shelf life? 

2. Or test for them as an indicator of shelf life failure? 

 

If it's 1, why not use heat instead?  If will change the flavour over time and possibly cause undesirable changes.  If it's 2 why is your heat processes not killing it off and why not use TVCs as indicators and pseudomonas spp. as likely spoilage indicators?

 

#2. This was after 90 days - it showed LAB. The other 4 samples didn't. I wonder if it wasn't properly sealed. 

[GMO]

Possibly.  But remember that only one sample showing contaminant doesn't make it certain it wasn't sealed, it just makes it certain you had presence of lactic acid bacteria in that sample.  Micro contamination can be "spotty".  It's not necessarily homogeneous.

 

Rather than focus on the bacteria, I'd look at RCA as the specific bacteria present aren't necessarily going to tell you much.  You know you've had a failure somewhere.  Now is the time to do a bit of investigation.

 

So I'd pull together a team and use a couple of tools:

 

Is / is not:  What Is an "Is/Is Not Analysis", and How to Conduct One?

 

Fishbone:  Ishikawa Diagram: A Guide on How to Use It | SafetyCulture

 

For both you will have to go out into your plant and process verify what is or isn't happening.

 

To jump ahead a little, I'd include in your checks:

 

How do you know the temperature is reached in the cooking process?  Can you be sure this is happening all the time?

How do you know there are never delays nor temperature drops on hot fill?  See if you can ask gently (without blame) as if that happens sometimes it could be a cause.

Have you swabbed your packaging and validated the hot fill will be effectively killing vegetative bacteria present?

How do you verify sealing?  Do you have standard settings for this?  If you check what the teams are actually running at, does it match these settings?  If you don't have standard settings but check randomly across shifts, what settings are present?  Do they vary?

 

Etc etc.  I'm sure you'll come up with more.