4 replies to this topic

[Procu1234]

Hi all,

 

Hoping someone can give me some advice here. I've read some similar-ish threads on this forum as well as a million other resources but feel I'm just getting more confused!

 

I manage a small production facility in the UK where we produce frozen ready meals. Our process (from the start of the cook stage) is fairly manual and currently goes like the below. For example, if we're making a curry - generally this is done in 50kg batches at a time:

- Raw food prepped

- Curry mixture cooked; internal temperature validated at 70C for 2 mins

- Curry mixture transferred to shallow trays and moved to blast chiller

- At this stage, the sauce has 90 minutes to go from 70C to 3C

- Once at 3C, the trays are removed one at a time and immediately portioned

- Portioned pots are immediately sealed and moved to the freezer. There is a 30 minute window from removing a tray from the chiller (at 3C) to the finished pot being in the freezer.

- Finished pots are then frozen down to -18C. Unfortunately we don't have the capacity to blast freeze (as well as blast chill), so once at 3C they are just sat in a walk-in freezer - time tests have shown it takes around 8 hours for them to get down to -18C.

 

So essentially, our current requirement is for the food to go from 70C to 3C within 90 minutes, and then into the freezer within a further 30 minutes. However, managing this in our small (and pretty understaffed!) space is getting harder as we get busier and it's occurred to me that we may be being too strict with these time controls?

 

We originally used these times/temps because a third party manufacturer (BRC) we briefly used followed these - when I then did our own assessment I essentially assumed this was best practice so we just went with it. Don't judge! From researching this more, I'm coming across so much different guidance but can't see if there's a specific regulation for our category - everyone seems to have slightly different rules for the chilling stage (ie. rapidly descending through the danger zone), and I can't seem to find any guidance around the subsequent chilled-to-frozen timescale?

 

FSAI states chilling to commence within 90 mins of cooking completion, then 120 mins to get from 55C to 10C, then 60 mins to get from 10C to 3C (so by my reckoning that's 270 minutes to go from 70C to 3C - seems very long??)

North Devon council states <8C in 90 mins

UK Gov just says 'A food business responsible for cooling any food which must, by virtue of this Part, be kept at a temperature below ambient temperatures shall cool that food as quickly as possible following—

1. the final heat processing stage; or

2. if no heat process is applied, the final preparation stage,

to the temperature at which, by virtue of this Part, it must be kept.'

Except this UK Gov one states 63C to 5C in 90 mins...

Australian FSA states 60C to 21C in 2 hours then 21C to 5C in 4 hours

So... I guess my question is, is there any fixed, regulatory time within which food should go from it's validated 'cooked' temperature (ie. the 70C) to it's validated 'cooled' temperature and then from there to it's final frozen temperature (-18C)? We have done micro testing to show our current method is achieving a safe final product, and I know it's probably unusual to be asking if we can 'loosen up' our processes, but even allowing ourselves an extra 30 minutes in which to cool the product down would help us massively. Am I correct in thinking that as long as we can still prove the safety of the finished product, we would be able to do this? Also, most sources seem to start the cooling 'timer' at 63C rather than 70C - since we remove from the heat at minimum 70C, this would then buy us some additional time I suppose...?

 

I should add: all our products are completely cooked prior to being portioned (ie. if you were so inclined, you could eat them as soon as they come off the heat - we don't portion with any raw meats etc) with the exception of IQF rice and pasta which is included at the portioning stage alongside the cooled 'sauce'. They are then stored and distributed frozen for the customer to also store frozen. Cook instructions are from frozen, and have also been validated.

 

Any insights/advice would be hugely appreciated - I'm winding myself in knots trying to work all this out (I am not a food tech by trade, very much wearing the hat as part of small-understaffed-company-life!). Hopefully that all made sense and someone can point me in the right direction at least!

Thanks in advance :)

 

 

 

[kingstudruler1]

Since no one else has chimed in, I'll try.  

 

Your cooking process achives a "X" log reduction in the number of pathogens.   Which basically means that there is a far less number of pathogens than prior to cooking.   However, scientifically, none wants to declare there to be "0".   For this reason we want to get the product out of the danger zone where bacteria can most likley reproduce and form toxins.  The danger zone is usually accepted to be 4-40C.  There is also a side aspect of spoilage organism growth as well.  

 

While the ones that you posted seem very different they really all say the same thing.   Some of them give more grace as you get to the extreme ends of the spectrum as pathogen growth is known to be slower at the ends of the range.  

 

In the absence of other data, I would stick with what your local goverment says.   What current validation data are you using if any?  just copacker recommendation?

 

In terms of freezing, I dont see that as a food safety parameter in your case - even listeria stops growing at about -1.5 to -4.   Am I correct?   Its more for shelf life?  I dont think you need to sweat the 4 to -18 time.   

 

How would elongating the cooling time help you?   Seems like faster would be better for output, food safety, etc.   I might not be understanding that portion of your question.   

Edited by kingstudruler1, 25 June 2024 - 04:58 PM.

[Procu1234]

@kingstudruler1 Thanks so much for your reply!

 

We are basically just going off our previous factory's process; we do send each batch we produce for micro testing and have always had results well within the limits that the previous factory had set. These are the maximum micro limits we are working to - we've never had an issue achieving this:

• Total aerobic count <100,000 per g

• Yeast and Moulds < 100,000 per g

• Salmonella – ND Not Detected

• E Coli – <10

• Coliforms <100 per g

• Staphylococcus Aureus  <100g

• Listeria Monocytogenes – Not Detected in 25g of sample

• Bacillus Cereus  <20 cfu/g

Where you've recommended sticking to what our local government says - this is my issue, as UK doesn't seem to provide one single requirement, although it looks like 63C to 8C or 5C in 90 mins is common.

 

That's good to know re freezing as I was struggling to find an exact requirement for this - I think you're right, it's more down to quality (quicker freezing = less ice crystals = better quality).

 

Re elongating the cooling time - it's just about providing us with a bit of wiggle room; our current process of getting from 70C to 3C within 90 minutes is really hard given that we only have 2 pretty basic chillers (no budget to buy better ones unfortunately!), but if we were able to make the limit for example 63C to 8C in 90 mins it will be that little bit more manageable for us. Due to the lack of chiller space, we do struggle to hit the 70 ->3 in 90 target...

 

I am planning to update our process to the following:

- Food cooked to internal temp of 80C for 6 seconds (more practical than 70C for 2 mins - avoids worker having to wait with a probe for 2 mins!) to achieve our 6-log reduction. In reality, the food is usually well over 85C at this point.

- Food transferred to shallow trays and cooled to 63C - is it acceptable for this cooling time to be excluded from the 90 minute cooling window (ie. the 'timer' only starts when it hits 63C)? We would use alarmed probes for this so as soon as it hits 63C, we know to start our 90 min timer.

- Once food hits 63C, it must reach 8C within 90 minutes (this is done in blast chillers). Would 5C be preferable?

- Once at 8C, food is either removed one tray at a time and quickly portioned, sealed and moved to freezer (this is done within 15 minutes) or transferred to chilled storage (<8C) where it is held for no more than 8 hours before being removed one tray at a time, portioned and frozen (again, the time between being removed from chilled storage and arriving at the freezer is <15 mins).

- Freezers set at -18C, no time target for food to reach -18C.

- Food is then stored at -18C, transported to our warehouse at -18C (where there are temp checks on departure/arrival plus temp log throughout the journey), then stored at -18C at warehouse.

 

Obviously we would then lab test the above to confirm that we are still hitting the previously mentioned micro targets.

 

I know there are no one-size-fits-all rules for these sorts of things but, in your opinion, does the above process look OK to you in terms of the basic time and temperature requirements, providing we can back this up with our micro results obviously?

 

Thanks for your help - even just bouncing this off someone else is a huge help as I am a team of 1 here so worried about making decisions with no other input!

[Shrimper]

I will chime in as well... The process that you described here looks safe to me. My thought/concern was about your 63C start time. I would try and take samples from your production line to see what the temperature coming out of the cooker is like. What is mean is to see what the temperature looks like after a minute, minute in a half, and 2 minutes to give a better (more accurate) starting point. 

 

The 5C versus 8C question, would 5C give you more time? If so, then I see no problem doing it. 

 

To me, the largest concern for micro issues is during the cooling stage. The blast chillers help you quickly reduce your temperature, so as long as they are not thawed and refrozen (and complies with the micros), then you should be good!

 

Hope this helps!

[Procu1234]

Thanks Shrimper - just so I understand, are you saying that you'd be checking to see exactly when the product is hitting 63C? When the cook stage is finished, the internal temp is usually around 80 - 90C; the plan is to then decant this into trays and keep a probe inserted with an alarm set so as soon as the temperature drops to 63C, we then hit our 90 minute timer (so from that point, we have 90 mins to get it to 8C).

 

Cooling to 8C before starting to portion would be logistically easier for us than cooling to 5C before portioning; generally we find getting things from 8C to 5C or 3C takes a disproportionately long time with our chillers so having 8C as our 'cooled' temperature would allow us to more easily meet our 90 minute time target. Bearing in mind once it hits 8C, it is quickly portioned (in under 15 mins) and moved to the freezer, so the time in which it is potentially rising above 8C is minimal.

 

Thanks both for your input, definitely putting my mind at ease! We are a very small site so I often get overwhelmed comparing ourselves to huge BRC manufacturers - the challenge is finding the right balance between compliance/high safety standards but ensuring it is actually practical/achievable in our space!