Urgent: bacterial growth in overloaded drying room

Hi all, thanks for reading my post.

The excitement was huge when our drying room was finally finished, and we loaded it up with wet biomass to dry it. So much, in fact, that the room was unable to keep humidity down. This created the perfect environment for a bacteria get-together, and we now have a full room of food waste with white/transparent colonies (Pseudomonas?).

We are an SME with lacking expertise on the issue at hand. Please bear with me and the following questions, that might be silly:

1. How is food waste with bacteria disposed?
2. If some trays look OK, will they still need to be discarded?
3. Should the drying room be emptied and cleaned before the next round?

Lesson learned: don't run a full-scale production with new equipment.

Hi all, thanks for reading my post.

 

The excitement was huge when our drying room was finally finished, and we loaded it up with wet biomass to dry it. So much, in fact, that the room was unable to keep humidity down. This created the perfect environment for a bacteria get-together, and we now have a full room of food waste with white/transparent colonies (Pseudomonas?).

 

We are an SME with lacking expertise on the issue at hand. Please bear with me and the following questions, that might be silly:

1. How is food waste with bacteria disposed?
2. If some trays look OK, will they still need to be discarded?
3. Should the drying room be emptied and cleaned before the next round?

Lesson learned: don't run a full-scale production with new equipment.

Hi Nicoline,

Sadly, it sounds like a gross failure of Process Knowledge.

Maybe a (drying) Consultant is required ?

Hi Charles,

I think you are right. I will list up my concerns and questions for the leadership and suggest we involve someone with more experience.

Dear Marigold,

Please, find some answers to your questions to help you further.

1. How is food waste with bacteria disposed?  --> That depends on the type of food and the bacteria, see hereunder. You can do a call with your local disposal agent, they will know how to advise you.
2. If some trays look OK, will they still need to be discarded? --> They look OK, however, it's likely that they are also Out of specification.
3. Should the drying room be emptied and cleaned before the next round? --> That's highly recommended and before the next round it will be necessary to have more process knowledge, to run it well.

"food waste with white/transparent colonies" --> Are these "colonies" visible on the product? If yes, then it are likely molds, which grow under humid conditions on the product surface (and they will contaminate your whole product) 

I hope you will succeed to learn quickly how to manage this annoying situation, so you can make the intended products.

Kind regards,

Gerard Heerkens

Dispose of anything that you can. Put it in bags twist them tight, and seal with tape before carrying them throughout the whole facility (and to be safe, spray the outside of the bags with a sanitizer solution and let them sit for 10 mins or so before moving them)

The entire drying room needs to be cleaned and sanitized and allowed to dry BEFORE you try again. And to be safe, you'll probably want to take air samples once it is dry as you may have introduced bacteria into the duct work (which is not the easiest thing to clean, you probably need sanitation specialists for that job)

Then, once you're sure you're not breeding anymore bacteria in the room, just do 1 part rack at a time. 

You should know on paper, what the moisture level MAXIMUM in the room can be, and how much moisture can effectively be removed at a time

Call the company who installed/you purchased it from and request that they send a process tech (that should have been included in the price IMO)

Good luck

Hi Marigold,

As an extra piece of advice, I would like to ask you to start recording relevant process parameters, if not done yet. You could think about some criteria hereunder. In the beginning you monitor more often (eg. each 30 minutes).

• Product temperature entering and leaving the drying room
• Product quantity in the drying room
• Line speed
• Temperature in the drying room
• Relative humidity (RH) of the drying room (when empty and with product)

You definitely need to know more about your product in the different process stages (Wateractivity, pH and temperature).

Kind regards,

Gerard H.

Thank you for taking the time to address my problem! Here follows an update:

The process technicians have been back and tweaked the system, as it was a technical error that stopped the system and not due to overloading. As we are under production pressure, it has been tempting to keep running full batches. We are disposing of quite a lot, sadly, but I am getting very useful feedback from this forum and from experience handling the batches so far.

When I can find the time in between production, I will prepare a list of actions and present to the leadership. It is tough to be the messenger saying that contaminated batches cannot be used.

Is there anyway to remove some moisture prior to entering the drying room? Like blast freezing for a short time first?  Just a thought

What exactly are you making?  This whole conversation is confusing to me, coming from a dry-cured Italian deli meat background, where we encourage humidity and mold growth :ejut:

Marshenko, the original poster said "biomass" seeweed came to mind for me, but I may be way off base

I would suggest denaturing the product as well, in order to ensure nobody who is dumpster diving tries to eat the product - you can purchase a blue denaturant dye ... or I've actually been forced by a USDA Inspector to use a bag of kitty litter in some chicken salads that were "produced without the benefit of inspection."  I couldn't convince him to let me take it home as it was perfectly acceptable product.  

Dispose of anything that you can. Put it in bags twist them tight, and seal with tape before carrying them throughout the whole facility (and to be safe, spray the outside of the bags with a sanitizer solution and let them sit for 10 mins or so before moving them)

 

The entire drying room needs to be cleaned and sanitized and allowed to dry BEFORE you try again. And to be safe, you'll probably want to take air samples once it is dry as you may have introduced bacteria into the duct work (which is not the easiest thing to clean, you probably need sanitation specialists for that job)

 

Then, once you're sure you're not breeding anymore bacteria in the room, just do 1 part rack at a time. 

 

You should know on paper, what the moisture level MAXIMUM in the room can be, and how much moisture can effectively be removed at a time

 

Call the company who installed/you purchased it from and request that they send a process tech (that should have been included in the price IMO)

 

Good luck