Chlorine wash water contact time
Hello all,
I have been reading about the contact time of chlorine water and produce in order to be fully sanitized. It looks like the general recommendation is at least 1 minute. Based on the below literature sources. Could anyone confirm this is the general recommendation or if there is another contact time recommendation of less than 1 minute?
8_Pub.3448-WashWaterChlorineDisinfection.pdf (lsu.edu)
Thank you!
Hello all,
I have been reading about the contact time of chlorine water and produce in order to be fully sanitized. It looks like the general recommendation is at least 1 minute. Based on the below literature sources. Could anyone confirm this is the general recommendation or if there is another contact time recommendation of less than 1 minute?
8_Pub.3448-WashWaterChlorineDisinfection.pdf (lsu.edu)
Thank you!
Hi anfrias,
Generalizations can be tricky.
Do you have a specific process in mind ?
Hi Anfrias,
I worked in Fresh Cut Fruit and Vegetable Processing and when you mention a chlorinated wash, I would assume there is an acid such as citric acid to balance out the pH? Our facility had a validation study done and we established a 2 minute dwell time with a free chlorine reading of 100-200 ppm and a pH of 6.0-7.0 was extremely effective for our process with an inline injection system to treat the water. With some produce (i.e., cantaloupes, watermelon, honeydew, etc.,) we would also do double washes or extended dwell times due to the nature of the rinds prior to them being handled, peeled, and cut.
I hope this provides a little insight.
Hi Anfrias,
I worked in Fresh Cut Fruit and Vegetable Processing and when you mention a chlorinated wash, I would assume there is an acid such as citric acid to balance out the pH? Our facility had a validation study done and we established a 2 minute dwell time with a free chlorine reading of 100-200 ppm and a pH of 6.0-7.0 was extremely effective for our process with an inline injection system to treat the water. With some produce (i.e., cantaloupes, watermelon, honeydew, etc.,) we would also do double washes or extended dwell times due to the nature of the rinds prior to them being handled, peeled, and cut.
I hope this provides a little insight.
Hi mb,
Thks input.
Can compare to OP.
IMO "it all depends" (on XYZ).
I daresay many people no longer use Cl2 although I suppose it's cheap and easily monitorable.
I'm a bit of a long time out of produce washing but from memory it wasn't about time it was about turbidity. What I remember reading is that the various biocide additives we often add to wash water in the food industry was to prevent recontamination. I.e. they are not acting as surface decontaminants. What they're doing is keeping the water "sweet" i.e. to not become fouled and become a source of contamination. It is the action of the water and the amount of movement of the water that dislodges pathogens.
BUT! There was an excellent paper recently from the chilled food association in the UK about how cut surfaces, particularly on onions resulted in increased adhesion of pathogens. So the amount of wash time may be dependent on when you'd cut the produce (and perhaps how much.)
https://www.chilledf...1-22-1st-ed.pdf
In any case, I never found evidence that any wash system containing whatever you liked (chlorine based, acidic etc etc) did anything more than 2 log reductions on a good day! So my caution is to look to the whole end to end supply chain not just your washing process because that will never be totally effective on its own.