Questions on peracetic acid

[Sulfur]

Interesting info. Unsuitable for soak tanks ok. But for a CIP buffer tank should be good for a work week (5 days but dependent on load also), especially if combined with some phosphoric acid for example.

[dick murton]

Sorry, but haven't looked at this for a few days

We have had problems with PAA residues with automated CIP systems, where either they go wrong and haven't scavenged out properly (OK OK, this is a programming / set up fault), or because the drainings from the wall have collected in sufficient volume, particularly in long in / out legs - below the level switch, for the residual PAA to affect the flavour. To be honest, we have never been exactly sure just how it gets in there as there are a multitude of possible reasons.

So by rinsing, we guarantee the CIP supply up to the spary head, the vessel walls and the outlet only contain water as the worst case scenario.

Obviously the problem is guaranteeing the water supply is sterile - and therein lies a major problem - just how do you consistently guarantee sterile water without using chemicals to ensure the water mains downstream of the steriliser , whether a sterile filter of UV, remains sterile at all times ?

However, I know the rinsing of PAA is a requirement of more than just our company, for the same reason - PAA contamination. I can't remember if this is now EU law, but if not technically law, people are getting so scared of "Chemical contamination" which has to be declared on labels.....

Can you imagine a food product label that says "may contain sterilant" ?? I know the wine makers have been doing it for years, and get away with it generally, but try something new and different and watch the sales drop through the floor.

CAMRA are pussy cats on the subject of CO2 blanketing cask beer compared to the response on this topic.

Re PAA degradation - the rate is very temperature dependant, so is much slower in a cold (zero to say +4 C) but with far lower kill effect than at say 15 to 20 C. The slightest contamination with organic material also speeds up the degradation - so poorly rinse kit dropped in a soakbath will wreck the effective strength far more rapidly than clean. The trouble is it still smells pretty much the same due to the acetic acid the PAA degrades to

As for a suitable soak bath sterilant - I don't think anything recently has proven as effective as iodophors - or certainly not when comparing price and "maintenance" required against that of iodophors

Keep looking

Oh yes and don't use hypochlorite - I once tried filling flat bottomed FVs which had been sprayed with hypo sterilant. Wonderful opportunity for a mass cold shower there were so many holes. (I tried it with water first as I supected this might be the case)