Combining Swaps in Environmental Pathogen Monitoring Plan

Hi,

We do composite swabs of certain areas. For example, we take a composite swab of the bottom part of the equipment in one area and then break the swabs down if there is a presumptive positive to determine the source of the positive.

the problem is---what then???? way more work for you in the event of a positive on your composite 

We run all swabs as individuals not composites

Scampi,

You make a good point. We composite swabs in order to save a little bit on testing. But when we receive a positive on the composite swab, we treat it as if all areas had tested positive and go from there, based on the assessed risks.

 

Hello everyone ;

 

There is something I want to discuss. Can we combine swaps taken from different points in Zone 2-3 and 4 ? You might think that different spots have the same risk? Let's assume that there are 10 workbenches in the sample production area. Such as taking 1 sample from 5 pieces and having it analyzed.

 

Thank you. 

 

Hi QAFE,

It's almost a textbook question.

The answer is well known for sampling an isolated lot of product for Salmonella.

Unstated which pathogen is involved but assuming it's a zero-tolerant one a basic answer is spelled out in post 3.

One might add that it also seems intuitively  illogical to mix samples from regions which have already been separately risk categorised.

If yr results on individual samples are routinely negative, you may choose to play roulette  by appropriately combining (assuming you can demonstrate that no analytical sensitivity is thereby lost).

I'm with charles and scampi

There really is no reason to combine swabs other that save money.   I'm all for saving money and I think there are legitimate way for quality and food safety personnel to make a positive financial impact.   However, this probably is not one of them.