Sampling size to prove the effectiveness of hand washing?

Hi,

I would like to know the sampling size to prove the effectiveness of hand washing. What percentage of the total staff has to be hand swabbed. Is there any official recommendation.

Thanks in advance

bhuvana

I'm no micro expert but first of all I'd ask your lab. Secondly, whatever you chose, be consistent. I tend to use a 10 by 10cm area as a guide for swabbing but you'd have to judge that on a hand (you don't want to encourage people only to swab palms!)

Bhuvana,

As far as my knowledge, there is no official recommendation as hand swabs are used to assess the levels of bacterial contamination and also from that you can understand level of supervision & training required to improve the hand washing practises.
Initially while starting on trial basis you can start with 20% of the group - whom really involved in direct handling of food. If you find the contamination level is more - then you have to plan for your supervision and training. After your training - you can again check for monitoring.
As GMO said - 10 x 10 cm area is recommended.

Rgds,
anish

Hi,

I would like to know the sampling size to prove the effectiveness of hand washing. What percentage of the total staff has to be hand swabbed. Is there any official recommendation.

Thanks in advance

bhuvana

Ah, I may have misunderstood what you meant by sampling size!

If you're asking "how many people should I swab?" then it greatly depends on factory size and your results. Initially in a new factory you might want to swab a high proportion to check the training has gone in then scale back if the results indicate it's fairly in control. I suppose not less than 10% of factory shop floor staff (including engineers and occasional visitors like management) would be a sensible target once the procedures are bedded in and I suppose given time you may feel confident enough to drop back to 5% if you have a large factory and the time taken for swabbing has become onerous but remember in a large factory it can be even easier for bad practice to become the norm so think seriously before cutting back too much. It's also important IMO to ensure all shifts and all times of day are covered. Cleaning staff are just as important as staff on production lines.

As ever, review, reassess. If you start getting an uplift in problems, investigate, increase swabbing generally for a while to increase focus, retrain etc. Probably not a bad idea to have different people taking swabs at unusual times as well (just to keep folk on their toes!) I often audit with a few swabs on me and it can increase the value of an audit to swab someone after handwashing as you go and possibly a piece of equipment. It might catch something that someone on a routine "I do this every week" kind of visit might miss.

Dear GMO and bhuvana),

I suppose not less than 10% of factory shop floor staff

Wow! That should take care of the budget. Perhaps a maximum absolute sample size also?

weekly basis ?

distribution / risk prioritised,? ie what is the process (as per Anish) ?

I think i would initially also (randomly) bias for some suspect candidates, in a nice way

I presume we are only talking about plate count here ?.

Rgds / Charles.C

Clarification-are the swabbing references for a plate count or an ATP swab??

thank you very much for all the feedback. We planning to do a TPC with 10% of the population selected on the level of risk associated with their location.