Chlorine Wash CCP

I'm wondering if we should be testing our chlorine levels for our wash water (we work with produce) for free chlorine rather than total chlorine. Currently we test Total Chlorine and the pH. Any advice? Any references that support one way over the other?

Thanks!

Yes, it should be free chlorine and not total chlorine.....think of the fun the auditor would have! The ph is required so you can dose the chlorine correctly. If your testing for total chlorine, how do you know how effective if at all it is? You could very well be spending $$$$ for zero benefit.

If you check for total chlorine at minute 1, it could be zero by minute 2 depending on the level of material on the veggies

I completely understand the issue between measuring total vs. free (total could be 200 ppm while at the same time the free is at 0, but you would never know it's not working anymore if you only measure total). Your response is exactly why we are thinking about changing it! :)

However, to make a change to our CCP, I need some scientific backing to support it. Know where I should look? I've been googling and searching journals all day but not really finding what I'm looking for.

I completely understand the issue between measuring total vs. free (total could be 200 ppm while at the same time the free is at 0, but you would never know it's not working anymore if you only measure total). Your response is exactly why we are thinking about changing it! :)

 

However, to make a change to our CCP, I need some scientific backing to support it. Know where I should look? I've been googling and searching journals all day but not really finding what I'm looking for.

Hi Buckeye,

Perhaps also a question of definitions/usage situation. And maybe also the measurement technique.

http://www.georgfisc...total-chlorine/

https://www.taylorte...SP?ContentID=20

Hi, Buckeye;

I think the CDC has published a good article on residual testing;

chlorine residual.pdf   230.41KB   163 downloads

Hi Slab,

It might be worth noting (and similarly to my post) that o-tolidine is (debatably) considered carcinogenic. I stopped using it for testing for chlorine many years ago. It also only measures total chlorine.

https://en.wikipedia.org/wiki/Tolidine

MSDS - TCI-T0255.pdf   100.32KB   50 downloads

The WHO mentioned limit (0.5ppm) of chlorine in drinking water would be regulatory unacceptable in some countries. Equally it is also possible to find a regulatory tolerance of 10x this limit elsewhere. USA I have no idea.

In canada, if i was to use it for washing poultry, it would be a cap of 200 ppm for a final rinse

Hi Slab,

 

It might be worth noting (and similarly to my post) that o-tolidine is (debatably) considered carcinogenic. I stopped using it for testing for chlorine many years ago. It also only measures total chlorine.

 

https://en.wikipedia.org/wiki/Tolidine

MSDS - TCI-T0255.pdf

 

Most titration kits contain nasty reagents that should be no where near food (my drop kit for peracetic acid as an example). Unfortunately manufacturers of said chemicals make as many assumptions as their end user does when it comes to safety. Pads and strips are much safer to handle in a food manufacturing environment. 

I only provided the attachment for good definition of terms.

It should still be 4 mg/l in the US.  If needed I can provide source for that.

 

Hi Slab,

Thanks for info. Indeed (similar limit to UK I believe).  IMO, not too many people will happily drink water at 5ppm free Cl2 unless no choice.  Smell is near-offensive IMEX.

Getting back to the OP,  reference was to fresh produce. I assume raw. RTE or not unknown. Product / process unknown. Location washing stage unknown.

Not my product area but in general the "Cl2" level and the terminology  could IMO depend on all the above but in practice the customary  terminology is probably as indicated in my earlier post/link.

If the OP was talking about something like a hydrocooler the usual CCP refs i have seen are usually in the 1-5ppm "Cl2" range. Not 200ppm.

However some (cruder?) fresh produce processes afaik have wash steps where ca. 200 ppm of "Cl2" is mentioned. From memory bean sprouts USA regulatory require X thousand ppm "Cl2".

(OT - USA importers at one time routinely requested all their raw seafood products to be dipped in 1000ppm "Cl2" before freezing. Maybe they still do.)

i guess for an organically loaded fresh produce system/process, free Cl2 is the logical  parameter.

@Buckeye - As per above, you may have to provide a little more info. regarding yr product/process/ step if you wish for a quantitatively meaningful source reference ?

Here is a presentation from the Center for Produce Safety about the use of chlorine in Produce Wash Water on "Small -  Sacale" oeprations.

Antores, that ppt was very helpful. Thanks to everyone who has responded! :)

Top Ice applied to a product to be considered a CCP?, if the ice is treated with a PA that is monitored, ice has been tested for microbial, facility is supplied by municipal water source, but is also tested for microbial as it is employee drinking water.