Adding Chlorine in recycled wash water for vegetables
Another thing I am confused about is that everywhere I am reading says something like "Chlorine that's commonly found in household bleach." But you don't want to wash vegetables with bleach?
Thanks so much! Also this is for a fresh vegetable packhouse.
I look after a vegetable processing facility and we use chlorine. We purchase it through a company called Ecolab, they have a product called XY12 (please note i have no official affiliations etc) i am pretty sure that they would have an agency near you somewhere, they are a global organisation. If not then i am sure one of the bigger chem supply companies should be able to supply it to you.
Quite often the companies that supply cleaning chems to food factories often have a chlorine product to use in wash water, they can usually help you out with concentrations, training on how to measure, safety training etc frequency of measuring etc. If they cant then i would not use them.
If you do go adding chlorine, be aware that you will probably have to add something like citric acid as well to keep the pH in the desired 5.5- 7.5 range, dependant upon the amount of chlorine you use and the pH of your water etc.
You are correct, pool chlorine would not be suitable for food contact purposes.
As an aside, whenever people say something like you cant wash vegies in chlorine because chlorine is in bleach etc, you can pretty much guess that they have a weak understanding of chemistry. Just because it is present does not mean it will behave the way it does in other chemical prepartions/molecules, for example chlorine is also in salt, nobody would say but Cl is also in bleach, you wouldn't eat bleach would you?
Hope that helps.
Bawdy
Hello Melsky.
If you are in the USA, all food contact chemicals should be labeled for the intended use, in this case, the chlorine is considered a pesticide and should be labeled for use in vegetable wash. The problem is that not a lot of liquid chlorine brands (Sodium Hypochlorite) are labeled for produce/vegetables. Do not buy “Clorox”since it may have lower concentration and/or fragrances.
The brand we use is called AGCLOR 310. It is just sodium hypochlorite at 12.5%, but is labeled for produce. The manufacturer is DECCO www.deccous.com (not endorsing or not affiliation).But you can look for other suppliers such as Ecolab (as recommended byBawdyo1).
Now, Chlorine is an effective and low cost chemical to use in produce wash, BUT it needs to be controlled and you need to know what you are doing. First, you need to keep the water pH, and normally would have to use an acid solution to keep the optimal pH.(Citric or Phosphoric Acid). Then you need to control turbidity (how clean is the re-circulating water) and of course you need to measure the free or active chlorine (not the total chlorine). How you do all this depends of your operations, so you need to do some test and validations.
Here are few good resources:
Chlorine use in produce packing lines: http://edis.ifas.ufl.edu/ch160
Chlorination of Water for Fluming and Cleaning Fresh Fruits and Vegetables and CleaningEquipment: http://onfarmfoodsafety.org/wp-content/uploads/Chlorination-of-Water-for-Fluming-and-Cleaning-Fresh-Fruits-and-Vegetables-and-Cleaning-Equipment.pdf
Hope that helps.
Yes, ORP is a measurement of the “killing” potential of the sanitizerin the water, so you are not measuring chlorine per se, but the “oxidation reductionpotential” (or killing potential). ORP is measured in millivolts (mV) . Research has shown that at an ORP valueof 650 o 700 mV, decay, spoilage and pathogenic bacteria such as E.Coli andSalmonela are killed within 30 seconds.
You may still need some pH testers (Most Manual ORP’s testers have pH readings as well) and Free Chlorine Testers (Strips) so you can measure the pH and Free Chorine, but once you get the desired concentrations you can use the ORP values to monitor.
Here is a link to know more about ORP. This particular company sells automatic ORP systems, which basically measures and injects the required amountof chemicals (Acid and Chlorine) in order to maintain the required ORP. This would be the ideal way to do it, but you can do it manually, depending of your system. Either way they have good resources: http://www.pulseinstruments.net/orpmain.aspx
Here is another free publication you can download: http://anrcatalog.ucdavis.edu/pdf/8149.pdf
AND even a link for a manual ORP meter: http://www.qasupplies.com/cowaphorptet.html
We use both automatic and manual systems. Of course, these equipment needs some calibration so you would have to add a calibration program, especially if you have an audited food safety system in place.
Again, not endorsing any of these.. just for your reference.
Hello Melsky.
If you are in the USA, all food contact chemicals should be labeled for the intended use, in this case, the chlorine is considered a pesticide and should be labeled for use in vegetable wash. The problem is that not a lot of liquid chlorine brands (Sodium Hypochlorite) are labeled for produce/vegetables. Do not buy “Clorox”since it may have lower concentration and/or fragrances.
The brand we use is called AGCLOR 310. It is just sodium hypochlorite at 12.5%, but is labeled for produce. The manufacturer is DECCO www.deccous.com (not endorsing or not affiliation).But you can look for other suppliers such as Ecolab (as recommended byBawdyo1).
Now, Chlorine is an effective and low cost chemical to use in produce wash, BUT it needs to be controlled and you need to know what you are doing. First, you need to keep the water pH, and normally would have to use an acid solution to keep the optimal pH.(Citric or Phosphoric Acid). Then you need to control turbidity (how clean is the re-circulating water) and of course you need to measure the free or active chlorine (not the total chlorine). How you do all this depends of your operations, so you need to do some test and validations.
Here are few good resources:
Chlorine use in produce packing lines: http://edis.ifas.ufl.edu/ch160
Chlorination of Water for Fluming and Cleaning Fresh Fruits and Vegetables and CleaningEquipment: http://onfarmfoodsafety.org/wp-content/uploads/Chlorination-of-Water-for-Fluming-and-Cleaning-Fresh-Fruits-and-Vegetables-and-Cleaning-Equipment.pdf
Hope that helps.
Dear Antores,
Thks for the interesting links.
It's not really my area but i noticed the recommendation in the 2 documents was considerably different regarding the target level of free (available) Cl2,ie 2-7 ppm in Canadian case compared to 100-150 ppm in US case.
Is this because the recycle functions are typically being run in a different way, eg maintaining different amounts of organic material, or difference in perceived pathogen "killing" requirement, or simply that the US likes to use a lot of "chlorine" ? I do remember that most vegetable HACCP plans I have seen typically have a CCP (or control level) for the wash water stage nearer to the lower range mentioned above.
I noted the caveats regarding choice of calcium hypochlorite in weblink. IMEX with plant water chlorination systems, the author was maybe optimistic. It has an advantage in being available in a solid form as long as one can tolerate the constant odour of Cl2 when handling. But it can also be extremely effective in blocking lines due to the generation of insoluble solids. Rather than adding a preliminary sedimentation unit I gave it up after a few months and switched to NaOCl solutions, problem solved.
Other commercial Cl2 washing sources for vegetable growing have also been discussed in this forum. From memory there is a long thread here on the use of isocyanate (?) based tablets (similar idea to that for pool use i believe). Seemed likely to be expensive compared to NaOCl but also seemed very simple to apply.
In terms of quality control, a common source of NaOCl liquid is as a by-product. It should, at a minimum, presumably match the drinking water limits for heavy metals and related impurities. Solid formulations are commercially available specifically for food use but IMEX the cost is very high.
Rgds / Charles.C
Recently noticed these 2 items which may be of interest regarding yr chlorine query -
a310- Determination free chlorine to prevent EcO157 cross-contam. fresh produce.pdf 406.99KB 83 downloads
a311 - Webinar slides Produce washwater management sep.2012.pdf 3.43MB 91 downloads
It seems that numerous variables are potentially involved and that an ideal dosage will likely depend significantly on the actual situation.
Rgds / Charles.C
just a comment for exporters: This kind of water management is not permitted in Europe.
Rgds
moskito
What can you tell me about chlorine in recycled wash water? Where do you purchase it, and what kind? I don't think you could just buy chlorine from a pool store and add that to the water?
Another thing I am confused about is that everywhere I am reading says something like "Chlorine that's commonly found in household bleach." But you don't want to wash vegetables with bleach?
Thanks so much! Also this is for a fresh vegetable packhouse.
Strongly recommend L-Lactic acid in stead of Chlorine which is safe, effective and less impact on product sensory characteristics.
Dear FLXY,
Can you suggest any accessible info. to validate yr statement ?
Rgds / Charles.C
Hi All,
I need some assistance.
I also work in the fresh produce industry and we are currently experiencing issues with our sanitation bath.
Our specification is as follows:
pH: 6.5 - 7.5
PPM: 65 ppm - 95 ppm
We have been able to achieve the specification, however for the past 2 weeks I have noticed that the pH of the water before adding chlorine is between 6.5 - 7.5 however once we have added the chlorine the pH fluctuates tremendously.
I have changed the pH meters so that I could rule out equipment malfunctioning.
What do you the possible issue is? Should i add citric acid to the water to bring the pH in line ?
Your assistance will be greatly appreciated.
Kind Regards,
Ashnee
Hi Ashnee,
I suggest you have a look at some of the links /attachments in earlier posts. The bactericidal effect requires control of pH.
So, assuming there are no product/Regulatory reasons otherwise, the answer is presumably Yes.