8 replies to this topic

[poppysnoss]

Does anyone have a recommended concentration for use of sodium hypochlorite for use with disinfection of fruit/veg. I am thinking 30-50ppm? Is this ok, do you think? (This is not usually my area!)

Mucho thanks in advance!

[Charles.C]

Dear Poppysnoss,

I think from memory, it's typically nearer 100ppm but someone else in this area will no doubt confirm or otherwise. If you want to do some searching first, there is a quite detailed thread on this topic here originally started by MAX. (just filter his posts)

Rgds / Charles.C

added - 50 - 150 according to this thread

http://www.ifsqn.com...?showtopic=4695

[Marzena]

Dear Poppysnoss,
I work for company using sodium hypochlorite-concentration of free chlorine in our washing tanks 80-120 ppm
redards,
Marzena

[AS NUR]

Dear Poppysnoss,

In water treatment plant, Typical Chlorine Dosages of Sodium hypochlorite is 0.2–2 mg/L

[Saviour]

Dear Poppysnoss

See the attachment. This may solve your problem.

Regards
Monika

Attached Files

•  Chlorination_in_fresh_fruits___Vegetables.pdf   172.87KB   109 downloads

[Charles.C]

Dear Monika,

Thks for this document. Interesting and useful compilation. Might add for the non-chlorine users here that 1 microgram/ml = 1mg/L = 1ppm (approx)

Did note that no refs after 1997. I had a similar problem when researching links in other posted thread. This necessitates some careful checking of any current local regulations.

I think there are a few practical aspects omitted in the document, eg sodium hypochorite liquid 10% is already not easy to handle IMEX but the calcium version is far worse for the operator and also tends to clog up the system. A newer option discussed in other thread but not mentioned in this document is claimed (I think) to reduce these problems (at a cost of course). In practice my guess is that many operatives still use the traditional chemicals as discussed here.

From memory, the major bacterial decline in early stage treatment derives primarily from the actual washing and the applied “available chlorine” helps to maintain an effective “clean” system rather than for its intrinsic microbiocidal effects on the product.. The usual operational problem as I think discussed in earlier linked thread is that the level of applied Av.Cl2 rapidly falls and becomes ineffective. In reality people would surely prefer to use lower levels of Av.Cl2 but cannot.

Rgds / Charles.C

[poppysnoss]

Thanks ever so much, everyone. That's really useful.

I hope I can return the favour. :)

[sandy soni]

Hi all,

Our company is installing a WTP (water treatment plant)...How much available chlorine can be present in potable water and to do so
how to do the dosing, strength of stock solution...how much chlorine to be added/liter of water
for making stock solution. Is anyone have calculation part on %chlorine in water and hyprochlorite solu.

Please help

[Saviour]

Dear Sandy Sony

You can refer the Hand book 'Analysis and Quality Control for Fruits and Vegetable products' by S. Ranganna, where in Chapter 'water standards & analysis' you will find the calculation for residual chlorine.

Also you shall refer IS 10500 for drining water quality and IS 4251 for process water quality.

Chlorine dosing pump may be syncronized with water pump by adjusting strocks of chloring dosing pump.

Regards
Monika