Ice crystals inside packaging? Help
Hi All
I hope somebody will be able to help me over this issue. We are producing red meats, our new project is to introduce a frozen range 'ready to cook from frozen'. Meats will go into aluminium trays simply sealed. It seems very simple but we struggle with ice formation during the freezing process. it looks like the ice crystals forms inside the packaging on a film, making product invisible.
We have a strict temperature control during processing, so meats are kept below 4C, then we place them into freezer ( -18C), are we doing something wrong??
Hi All
I hope somebody will be able to help me over this issue. We are producing red meats, our new project is to introduce a frozen range 'ready to cook from frozen'. Meats will go into aluminium trays simply sealed. It seems very simple but we struggle with ice formation during the freezing process. it looks like the ice crystals forms inside the packaging on a film, making product invisible.
We have a strict temperature control during processing, so meats are kept below 4C, then we place them into freezer ( -18C), are we doing something wrong??
Hi anna,
Some possibilities here -
The humidity level is too high on the meat prior to freezing. As they air cannot move effectively from the inside to the outside, the water is forming crystals.
There are a couple of ways to handle this, but at my previous post, we finally got CFIA to allow a trial to package prior to blast freezing (but the film was perforated) That way the product didn't come back out where the surface would warm just enough to release the moisture onto the surface, then crystallize when it went back into the freezer
What exactly are the steps your using now? This is a combo problem of temperature fluctuation (not abuse) and humidity control
HI Scampi
our steps include chilled delivery, chilled storage, processing ( room temp about 6-8C) meat not above 4C, then blast chilling and freezing. Our freezer runs at -18C.
I tried different methods,
1 packing and sealing prior to freezing- really bad results, products not visible at all
2 freezing for about 1 hr without sealing and then seal and pack - not bad, however some ice crystals appeared
3 finally freeze for about 2-3 hours and pack- we had a freezer burns:(.
I'm not sure what we shall do.
The only thing it would appear you've not tried yet, but it maybe worth a shot, is covering the meat even if it's plastic wrap, making contact with the meat prior to blast freezing for 2-3 hours then packaging.
OR reducing the temperature of your packaging room to 4C ( that's what I kept the packaging room at)
I know there are some dips on the market for meat, but I don't know if any of them can help with the moisture level on the surface of the meat
Is this MAP packaging?
Also, do you know the velocity of the blast freezer? And have you done freezing validations yet? It helps to know the speed that the meat reaches certain temperatures to aid in this process
It really is trial and error
HI Scampi
our steps include chilled delivery, chilled storage, processing ( room temp about 6-8C) meat not above 4C, then blast chilling and freezing. Our freezer runs at -18C.
I tried different methods,
1 packing and sealing prior to freezing- really bad results, products not visible at all
2 freezing for about 1 hr without sealing and then seal and pack - not bad, however some ice crystals appeared
3 finally freeze for about 2-3 hours and pack- we had a freezer burns:(.
I'm not sure what we shall do.
Hi Anna,
If your blast freezer runs at an air temperature of -18degC then something is seriously wrong with it. Or it is overloaded,
HI
Thanks for answers. Yes the freezer is overloaded and it is not a blast freezer ( old one). we are currently in process to get a proper blast freezer, which be able to freeze meat much faster. I'll do the freezing validation then :).
You will be amazed at the difference the blast freezer makes on quality! The rapid freezing changes the size of the ice crystals that form not only on the surface, but within the product as well.
Since you've got an old freezer that's overloaded, you really can't do much about the ice right now
The blast should run at about -25C with velocity of about 4m/s so you get rapid moisture removal
NOTE: you may find that this kind of freezer needs to be shut down and defrosted regularly depending on the initial moisture level of your product
You will be amazed at the difference the blast freezer makes on quality! The rapid freezing changes the size of the ice crystals that form not only on the surface, but within the product as well.
Since you've got an old freezer that's overloaded, you really can't do much about the ice right now
The blast should run at about -25C with velocity of about 4m/s so you get rapid moisture removal
NOTE: you may find that this kind of freezer needs to be shut down and defrosted regularly depending on the initial moisture level of your product
IMEX "Blast freezer" has a miscellany of meanings, eg simple fan-driven, tunnel, bare coil, continuous belt freezer. They all seem to have individual personalities
As you note, the air temperature typically depends on the load, compressor, air velocity, type of product, targetted freezing time.
IMEX <= -30degC is a typical design target under full load. But people just love to stuff every square inch of the room with something + buy inadequate compressor capacity. .
***TARGET*** Charles, in my experience, have been numbers floated by the manufacturer and are nearly impossible to get once in use
***TARGET*** Charles, in my experience, have been numbers floated by the manufacturer and are nearly impossible to get once in use
I agree that commercial system freezing performances are often "optimised". I have encountered all the below -
(a) Compressor purchased is intrinsically too low freezing capacity for Production volume.
(b) Inadequate maintenance of an adequate compressor system
(c) Overloaded.
(d) Input is too hot.
I have had almost identical experience with home air-conditioners . :smile:
Thank you for all that info. It is good to see what more experienced experts have to say. Thank you for advice and I'll be in touch when we get our new blast freezer:)
Thank you for all that info. It is good to see what more experienced experts have to say. Thank you for advice and I'll be in touch when we get our new blast freezer:)
TBH yr problem IMEX (not red meat) is more frequently found after freezing during Cold Room storage but that is rather different. And common.
JFI, what is the thickness of yr product to be frozen and approx. how long does it take to get the core temperature of slowest frozen product to reach -18degC ? 2hr/3hr/4hr ? >4hr (some factories freeze overnight due "speed")
IMEX (seafood), freezing unpacked product (2-3 hrs) demands plastic covering. Otherwise > freezer burn.
Freezing boxed, unglazed, inner-wrapped fillet product (2-3 hrs) gives variable appearances related to original "wetness/packing density".