Evaporation temperature for free chlorine in tap water

Dear all:

A friend of mine is doing the Hazard analysis for the incoming town water and she is wondering at what temperature chlorine in the tap water will be evaporated so that any excess amount is actually not hazardous to her end product (bakery product - wafer)?

TQ.

Dear YongYM,

Presume by hazardous you mean with respect to human health (not flavour etc) and that she is not doing anything extra to the water supply, eg adding more chlorine?.
I’m not a baker but I suppose any authorised manufacturing guide will specify the requirement for water to be (safely) used for her specific process, probably that it be “potable”. Is it ?

If she wishes to do a complete analysis of the effect of the chlorination, an investigation into residues from her process will be involved (good luck!), perhaps something like this one for washing vegetables with chlorinated water –

http://www.food.gov....haids200614.pdf

Rgds / Charles.C

Dear Charles:

According to her, the chlorine smell in the incoming tap water is sometimes very high and she suspects that the chrine level is excess. Her company has a simple filter to remove all the impurites e.g. 'sludge' etc but not chlorine. Her boss told her that even excess chlorine will not be harmful as chlorine in the tap water will be evaporated from the product once baked (more than 100'C) like what we normally do when boiling water before drinking.

Her question is only at what temperature chlorine will start to evaporate as the info. she obtained from internet is, the boiling point for chlorine gas is negetive degree celcius. She would like to add this statement in the hazard anylis worksheet to support her boss answers. ("even excess chlorine will not be harmful as chlorine in the tap water will be evaporated from the product once baked")

Any idea?

Dear YongYM,

Sorry delay in answering, I missed yr reply.

My initial suggestion is she checks the free chlorine level in the process input water (eg DPD tablets)) since this will be a bit more informative than her nose. Is that possible ? As you probably know, some processors routinely boost the "Cl2" content in the tapwater to (theoretically) help depress bacteria without causing any specific safety detriment to the subsequent cooked products AFAIK. Nonetheless I have also seen this idea taken too far (not baked products) causing noticeable flavour changes.

Rgds / Charles.C

added - I fear yr friend's idea rather invites an auditor question like "how much excess"

Dear YongYM,

Sorry delay in answering, I missed yr reply.

My initial suggestion is she checks the free chlorine level in the process input water (eg DPD tablets)) since this will be a bit more informative than her nose. Is that possible ? As you probably know, some processors routinely boost the "Cl2" content in the tapwater to (theoretically) help depress bacteria without causing any specific safety detriment to the subsequent cooked products AFAIK. Nonetheless I have also seen this idea taken too far (not baked products) causing noticeable flavour changes.

Rgds / Charles.C

added - I fear yr friend's idea rather invites an auditor question like "how much excess"

if the water she is using is town mains, and regulated by an "authority" then they will have legal standards that they have to abide by (well in UK anyway....supposedly!)
as charles said you can check chlorine levels using DPD no1 tablets and if i remember right if you add a dpd no4 tablet you get free chlorine.

In canning the chlorine levels are raised in order to kill off bacteria on the cans. Cans can be cooked at 126 degrees at pressure for up to an hour and a half and the chlorine dissipates.

Im not sure why she needs to add a statement in her HACCP?? Chlorine levels cannot be a CCP as you don't really have any control over the levels. Id just have the limits in her QCP set up and make them wide enough but not too wide