Chlorine - Safe Levels in product

Hi All

So, this is my first post even though I am a regular reader of the forums! Sorry if I am repeating a question that has already been asked....but I can't find it if it has been

I am trying to find some info- we are using local authority water in our factory which is potable. We are chlorinating in-house also (in my mind the need for this is questionable due to historical micro data I have when e.g. chlorine pumps not functioning correctly but it is required by our vets and can't be changed at the moment so take it that it is mandatory please!) and aim for 0.2-0.5ppm free chlorine. I inherited these limits so I don;t know the rationale behind those levels at the time. From reading the FSAI Guidance Note 8 which relates to beef & sheep slaughter plants they advise the levels should be maintained between 0.2 - 0.5ppm and should not exceed 1ppm. I am in a pig processors where we wet cure pork so obviously things are different for us.

My problem is two-fold:
1. What are safe free chlorine levels when the water is going to be pumped into product? I can see references to washing veggies etc in water but this case is different. For example, I know one of our suppliers uses 2ppm as their upper limit with a target of 1.2ppm but if I want to change our limits I need a very good reason to do so. Does chlorine dissipate (spelling??!) in product as I understand it does when in water? What levels of chlorine would cause adverse health effects in finished product? I don't think I have ever noticed a chlorine taste from bacon!!
2. What corrective action to take in the event of too much chlorine being present in the water? We check pre-curing but I obviously want to cover off worst case scenario. To do that though I kind of need an answer to the first question!

Hoping someone can help & thanks in advance

Dear Member,
'WHO' limits for safe drinking water are 0.2 to 0.5 ppm. Chlorine is volatile and dissipates fast. To maintain this level manually is difficult unless you have automatic doser. To know how long this water would be safe is to do TPC every hour. You will get an idea.
Regards, Sujit

Dear olok,

A few years back, Codex / FAO / WHO initiated a depth study on a risk analysis of this subject. It's probably still passing through the "steps". As a starter they compiled / issued a list of EC National limits for this parameter. The results from memory varied widely, essentially zero to finite numbers. Unfortunately I can't remember the UK level assuming there was one but the document should be available from FAO website and maybe has been updated. There may even be a conclusion.!

Rgds / Charles.C

Thanks Sujit- we do have an automatic dosing system so maintaining levels generally isn't an issue.

Charles- will have a look for anything on the FAO website, thanks for the info!

Dear olok,

I was unable to locate the ref. I remembered so hv had a look at yr apparently simple query. I appreciate your post was directly aimed at yr process but I extended it to the general water supply since that seemed likely to be easier + useful in the sense that if it was acceptable for drinking should be ok to apply to food (hopefully). Unfortunately the topic turns out to be a regulatory minefield however I think the info. below may assist a little -

The operational answer for UK seems to be here –

chlorine1.pdf   88.61KB   62 downloads

The background to above is, I suspect, complex vis-à-vis EC regulations. I think the EC have not issued a specific “chlorine” rule but they hv issued max. levels of things like “disinfection by-products” which has created a real mess of inter-related situations.

The basis for UK levels appears to be as per info. below from a book dated 2000 (AFAIK). Whether this is compliant with the EC regs is another matter and I won’t speculate due lack of any relevant data.
(How far the EC / sovereign right option comes into this I am not sure.)

\'chlorine\' in water.png   82.35KB   9 downloads

Some additional related extracts are here. At least one EC country does seem to specify (max.zero!). –

\'chlorine\' in water2, annex.png   226.26KB   11 downloads
chlorine in water3, 2006.png   112KB   9 downloads

This 2004 document details the overall quality compliance issue / EC regs for water for many countries. Just to illustrate the confusion.

water compliance to EC standards.pdf   160.07KB   37 downloads

Getting to the factory level, the concentration targetted will surely vary as you mention (and depending on CL2-chemical also of course). here is ("probably", since draft) an UK officially recommended level for a meat processor (MIG). Maybe equivalent to FSAI so pork excluded, didn't check ?, the MIG main manual is a free download on the net. Yes, Cl2 dissipates over time. no idea about smell/taste effects, hv never noticed either for seafood unless levels go crazy, eg 10+,(1-3ppm hypochlorite is common in many seafood factories (not UK)without any noticeable s/f that i know of. Above 5ppm you can usually smell it in the water so already debatable (= home?), and maybe taste it (EC water flavour reg. is ,from memory, purely organoleptic based). Some people are highly sensitive, eg non-smokers .
A corrective action is mentioned in my extract but didn't follow it up.

chlorine in water, MIG 2005.png   8.94KB   7 downloads

Subsequent to above refs, i found another (commercial) "pig - specific" document which looks impressive / fairly authoritative and seems to agree with UK comments above.
(might suggest a phone call to ask them if they know the official basis to their system in a maximum Cl2 sense - free info )

SWINE DISINFECTION PROGRAMME.pdf   104.07KB   26 downloads

Rgds / Charles.C

added - should emphasise again that the above application comments are directed towards UK. It is highly probable that some other countries will consider then unacceptable (possibly even too mild in some places ?)

Wow, thank you so much Charles for all the info. I look forward to looking at it properly on Monday when my brain is engaged I did find a FAO report on Chlorine but it is pretty lengthy & I haven't got to more than a quick scan yet. I will let you know if I get any more info. Have also put in a query to the FSAI so fingers crossed that between everything I'll get a definitive answer!

Thank you again.

Hi, Let's remember to control pH, too. Chlorine active especies do it best under slightly acid pH (near 6-6.5). Regards. Carlos.

Hi All

So, this is my first post even though I am a regular reader of the forums! Sorry if I am repeating a question that has already been asked....but I can't find it if it has been

I am trying to find some info- we are using local authority water in our factory which is potable. We are chlorinating in-house also (in my mind the need for this is questionable due to historical micro data I have when e.g. chlorine pumps not functioning correctly but it is required by our vets and can't be changed at the moment so take it that it is mandatory please!) and aim for 0.2-0.5ppm free chlorine. I inherited these limits so I don;t know the rationale behind those levels at the time. From reading the FSAI Guidance Note 8 which relates to beef & sheep slaughter plants they advise the levels should be maintained between 0.2 - 0.5ppm and should not exceed 1ppm. I am in a pig processors where we wet cure pork so obviously things are different for us.

My problem is two-fold:
1. What are safe free chlorine levels when the water is going to be pumped into product? I can see references to washing veggies etc in water but this case is different. For example, I know one of our suppliers uses 2ppm as their upper limit with a target of 1.2ppm but if I want to change our limits I need a very good reason to do so. Does chlorine dissipate (spelling??!) in product as I understand it does when in water? What levels of chlorine would cause adverse health effects in finished product? I don't think I have ever noticed a chlorine taste from bacon!!
2. What corrective action to take in the event of too much chlorine being present in the water? We check pre-curing but I obviously want to cover off worst case scenario. To do that though I kind of need an answer to the first question!

Hoping someone can help & thanks in advance