5 replies to this topic

[Procu1234]

Hi all, hoping someone far more qualified/experience can give me a couple of pointers!

 

We are a small production site making small-batch frozen ready meals. All our products are fully cooked on our site (including meat/fish etc, everything is totally cooked through), assembled and frozen where they remain frozen throughout the supply chain. Customer stores the meal frozen and reheats from frozen (instructions ensure core temperature target met - ie. made clear not to eat without heating, but obviously some people might ignore us and do that!)

 

We have 21 SKUs and send them off for micro testing. We get results on the attached indicators (see image).

 

We consistently get <10 / <20 on all indicators (and have only ever had not-detected on salmonella/listeria), so I have no major concerns around the overall product safety (and we've never had a food safety incident (touches wood!)). However, occasionally we will get a really high TVC but all other results still <10/<20. For example I've just had results back for a chicken curry where coliforms/e. coli are both <10 and B. Cereus / S. Aureus / Yeasts / Moulds all <20, but the TVC is 1,450! Last time this product was tested, everything else was the same but TVC was also <10.

 

I understand TVC is an indicator of overall microbial presence and that consistant high TVC suggests potential issues in the water supply, but if this was the case I would expect to see this in all our products, all of the time. Two other meals produced the day before and day after the above-mentioned chicken curry both had a TVC of <10. 

 

Generally it seems that the elevated TVC only occurs in meals with either chicken, fish or cheese - but still only shows up occasionally. We haven't changed any suppliers/ingredients/processes in over a year (so it's not like we changed fish supplier and suddenly got high results) - as far as I can see there's no obvious pattern, unless I'm missing something!

 

Does anyone have any insights into what could be causing this / how concerned do I need to be?

 

We regularly carry out environmental swabbing and have never had any issues.

 

Any thoughts greatly appreciated!

 

[GMO]

Hi!  Sorry I can't see an image?

TVCs are just a count of your total vegetative bacteria, i.e. the ones which aren't dead and aren't spores.  They're not just found in water but everywhere.  Sites use them as an early indicator of some failures in process or in their HACCP plan.  They are not normally dangerous in themselves.

 

It's absolutely possible to have high TVC counts and low or absent pathogen and yeast and mould counts because TVCs are everything that's there from a micro point of view whether it's dangerous or not if that makes sense?

 

What I'd do is get a big chunk of data for a few months if you can and order it by % failure.  Then if you take your top meals (failure wise) is there a common process or common ingredient?  If you can identify a common process or ingredient, test that or observe the process and test it. I did this once and found a vegetable cooker was being overloaded.  Fixed that and the problem went away.

 

If you can't get to a quick solution that way, then it's also worth testing all of the work in process for your worst offending meals before you assemble them. Then you can see which part of your process might be failing.

 

I'd also like to point out that unless you're cooking it, cheese is always going to be crazy high in TVCs because you add starter cultures to it and, in some cases, they might be being picked up by the test.  It might be worth thinking about checking those meals without any added cheese (if it's sprinkled on top) or using enterobacteriacae as a hygiene indicator just for those products if your customer permits it.  

 

Lastly and this isn't a great thing, there have been so many scandals over the years with labs and the odd employee not testing.  It's because it's badly paid and overworked.  I cannot read a "we've only just started to see a problem" comment on lab results without thinking about when I had to sack a lab employee for pretending to test samples she hadn't.  I'm not saying you shouldn't trust your results, you don't really have an option but sometimes absence of failure could be you just were lucky or didn't test the sample that would have failed and sometimes it's just a lab employee doing what some of them sometimes do.  But the message from that should be (after sighing a lot) that micro data can be "spotty" and if you are getting, say, 50% failures on TVC on a meal, I wouldn't look to the 50% passes and not investigate.

[chrisrushworth]

Hi!  Sorry I can't see an image?

TVCs are just a count of your total vegetative bacteria, i.e. the ones which aren't dead and aren't spores.  They're not just found in water but everywhere.  Sites use them as an early indicator of some failures in process or in their HACCP plan.  They are not normally dangerous in themselves.

 

It's absolutely possible to have high TVC counts and low or absent pathogen and yeast and mould counts because TVCs are everything that's there from a micro point of view whether it's dangerous or not if that makes sense?

 

What I'd do is get a big chunk of data for a few months if you can and order it by % failure.  Then if you take your top meals (failure wise) is there a common process or common ingredient?  If you can identify a common process or ingredient, test that or observe the process and test it. I did this once and found a vegetable cooker was being overloaded.  Fixed that and the problem went away.

 

If you can't get to a quick solution that way, then it's also worth testing all of the work in process for your worst offending meals before you assemble them. Then you can see which part of your process might be failing.

 

I'd also like to point out that unless you're cooking it, cheese is always going to be crazy high in TVCs because you add starter cultures to it and, in some cases, they might be being picked up by the test.  It might be worth thinking about checking those meals without any added cheese (if it's sprinkled on top) or using enterobacteriacae as a hygiene indicator just for those products if your customer permits it.  

 

Lastly and this isn't a great thing, there have been so many scandals over the years with labs and the odd employee not testing.  It's because it's badly paid and overworked.  I cannot read a "we've only just started to see a problem" comment on lab results without thinking about when I had to sack a lab employee for pretending to test samples she hadn't.  I'm not saying you shouldn't trust your results, you don't really have an option but sometimes absence of failure could be you just were lucky or didn't test the sample that would have failed and sometimes it's just a lab employee doing what some of them sometimes do.  But the message from that should be (after sighing a lot) that micro data can be "spotty" and if you are getting, say, 50% failures on TVC on a meal, I wouldn't look to the 50% passes and not investigate.

 

 

I agree with the above, Cheese will always spike on TVC.

 

Do you have the sample retested at the lab? Are they then in tolerance?

Or are you sending components for retest?

 

I have worked in fast paced labs, and now as a technical manager i see it from the other end.

Humans make mistakes, i can be as simple as not changing straws on dilutions ...

 

I would highlight the erroneous TVC count to the lab manager and ask them to retest. 9/10 it either a prep error/media error/reading error/data entry error...

Could also ask the lab for when they last did there UKAS challenge tests?

[kingstudruler1]

I would not be alarmed by 1450.  For comparison HTST milk has a regulatory limit of 20,000 apc or so depending on the country produced.  Or dehydrated spice might have a spec of 100,000.   

 

It is odd that it is not your normal result.   Because we dont know your process some possible reasons : contamiantion of sample, bacteria that can survive your thermal process (think thermophiles), inadequate cleaning of equipment after thermal process, contamination of equipment / product  after thermal process, (like others said adding ingredients after thermal process or possible lab error). 

 

One thing I have done in the past (for problems much more sever than yours) was to have the bacteria in the sample identified down to genus level.   Then search the process to find possible sources.   (may also help with identifying organisms that could survie thermal process).  

[Procu1234]

Hi all,

 

Thanks for the replies, really appreciate it! Apologies re image not attaching - hoping it now works:

 

 

Regards retesting - we have done this (sending another sample from the same batch) and the TVC has usually come back down at 'normal' levels (<10), but not 100% of the time. Which suggest to me more likely something happening at the lab end? Although I guess could still be happening during production - would need to test significant numbers of samples from the same batch to work this out and I think it would blow my budgets!

 

I am going to do what you suggest GMO re monitoring over time to identify consistent ingredients/methods. I agree that the cheese-containing dishes can likely be discounted (or at least noted as of less concern) as these are all dishes which contain a 'raw' sprinkling of cheese at the end (post-thermal treatment etc), so this is the likely culprit. For things like chicken curry though I'm more keen to see what themes there are. I will send a couple of batches of the cheese dishes off to the lab cheese-free though so we have firmer proof of this.

 

I like the idea of testing component parts also (ie. we can send off the rice, the chicken, the sauce as separate elements to see if there's a consistent culprit). If still no joy then I'll look into whether we can test right down to the specific genus level although I can already sense the pushback from my higher ups on this one as I'd imagine it will be very expensive...!

 

Thank you for all the suggestions - much appreciated!

 

 

 

[Procu1234]

Honestly struggling so much with the image. Easier to just type the darn thing!

 

Total Viable Count, 2 days

Coliforms (presumptive)

Escherichia coli (β-Glucuronidase positive)

Coagulase positive Staphylococci (Presumptive)

Bacillus cereus (presumptive)

Yeasts

Moulds

Salmonella sp. (ELISA)

Listeria spp. (ELISA)