5 replies to this topic

[AJL]

Hi,
I had a costumer asking if we do allergen settle plates.
1) seriously what is this
2) has anyone got a procedure/SOP for it

[kconf]

Testing for allergen using petri plates? 

[KellyQA]

I have never been asked to do allergen settle plates, but settle plates are passive air samples that are used to detect airborne contaminants, such as airborne food allergens. 

 

I would imagine that it would be a very similar process as ambient air testing, where you place agar plates in the production areas, leave them open for a period of time and then send them to a lab to be analyzed. I would get with the lab that you use and state that you want to do passive air sampling for allergens. They should be able to provide you with the right information. Sampling time may be longer than just standard ambient air.

 

Here is a passive air sampling procedure that I have used in the past. This was for Yeast, mold, APC, but should be similar. I would assume that instead of testing for yeasts and molds, the lab would test for whatever specific allergens you need to test for. 

 

Passive Air Sampling

1. Always wash and sanitize your hands before proceeding with any sampling.
2. Allow the refrigerated agar plates to come to room temperature before using.
3. Examine plates for contamination or liquification from condensation.
4. Note: Do not use liquified plates or plates with growth on them. If you notice this, please contact the lab for new supplies. Using permanent marker, label the plates or apply a pre-printed label.
5. Clean visible debris and area with sanitizer before placing petri dishes.
6. Transport plates to desired testing area (preferably a flat surface) ensuring the petri dish lids stay secure.
7. Aseptically open plates with media side down and place covers on the sanitized surface. Do not touch the agar or inside of the petri dish.
8. Allow the surrounding air to settle on plates for 15 minutes.
9. Close plates aseptically without touching the agar, and seal it with tape or parafilm. This avoids the lid separating from the plate and potentially contaminating the sample.
10. Re-sanitize surfaces where petri dishes were placed.
11. Refrigerate after sampling until ready to ship/deliver to the lab.

Note: Do not freeze agar plates! Freezing can kill microbes and could result in false low counts.

[Brothbro]

KellyQA seems to be on the right track, this is also what I would assume. I personally have never heard of this method for allergen testing either. Below is a link to a UK gov agency that also references allergen settle plates in their allergen safety glossary, so this concept does indeed seem to have some precedent.

 

https://www.food.gov...eaning-glossary

[AJL]

I would just test myself with the LFD but seriously it seems so abstract. Do I swab the plate then? Obviously just an empty petri dish and not one with agar.....I guess?
And what does the result even mean? Even if I got a quantitative answer from the lab thats a lot of calculating to work out how contaminated the air is....
How long do I leave it? Where do I leave it? I want an SOP haha.

[Dorothy87]

Hi AJL  

 

Allergenic ingredients in the form of dry powders, such as powdered eggs, milk and flour can be readily dispersed in the air and may cross-contaminate other products by settling into ingredients bins, or onto open product or cleaned surfaces. 

 

Air sampling may be required to : 

 

- validate that segregation of areas that do and do not handle allergens are effective

- validate effectiveness of air flow systems 

- investigate potential cross-contamination risk due to the production of aerosols when cleaning 

 

A simple way to sample allergens that settle out from the air is by placing open, empty settle plates in the manufacturing environment for a defined exposure time during particular activity (during production/ after production). The contents of the settle plates are testes for allergens. Alternatively a known quantity of extraction solution or product can be placed in the settle plates (speak to laboratory, they should know) which can be tested for allergens. 

 

Consider the time wisely, for example settle plates exposed to the air for one week may show contamination which allergenic material, but if product is only open to the air for a max of a few hours then leaving settle plates open for a week is not appropriate. 

 

Not sure what you manufacturing but, I would leave plates next and slightly away to dry allergens for example flour (gluten) while sieving process. 

 

Do you have allergens claims? For example eggs-free etc 

 

Settle plates are referred to as passive air sampling devices, as only particles of sufficient size and weight settle onto the surface in the exposed period. Active air sampling devices force samples air through a filter at controlled rate; the filter can then be easily removed and analysed following a liquid extraction. 

 

I used Campden BRI guideline no. 71 - Food allergens: practical risk analysis, testing and action levels.