40 replies to this topic

[GMO]

I came across acetic acid being used in a factory. I scoffed at it initially then did a search. Turns out some organic acids have better bactericidal properties than you’d think. It’s not just linked to pH; it seems to be the organic acid itself which has the effect. Although having said that, the acid was used as a pre dip for certain vegetables, then rinsed and then put through a chlorine wash (at about pH 6 – 7.5). I wondered whether some of the effect was due to surface molecules being acidified by the dip which caused localised chlorine production (without chlorine gas production). Either way, it worked.

If you have a search around in the scientific literature though about hypochlorite use in washing, it’s very interesting because there’s not much scientific basis for it. I remember reading in one paper (which unfortunately I can’t remember where it was) that the hypochlorite doesn’t kill bacteria on the vegetables but keeps the water clean; it’s the turbidity of the water which actually cleans the vegetables and the hypochlorite just prevents recontamination if the water is used again. Interesting eh? Certainly some retailers are using water only to wash ready to eat lettuce now.

I wonder if there is a potential for UV?

[cazyncymru]

Hi Jean

i've used peroxide to sterilise packaging before being filled with a UHT product.

Caz x

[GMO]

I've used peroxides in equipment cleaning before (but as an occasional blast rather than routine use). I would suggest that peracetic acid is probably your best choice if you wanted to start a literature search - sure it's unpleasant but I'd prefer people used that than hydrogen peroxide also you're using hypochorite at the moment! The benefit with peracetic acid is once it's oxidising power is exhausted, it will revert to acetic acid which will have the benefit of an antibacterial effect as well. I suspect you will need rinsing afterwards though due to potential vinegary taint but for some ingredients that might not be an issue.

[Jean]

Dear GMO,

Thanks for the info on peracetic acid. I came across the supplier who claims that peracetic acid based product they have is a “no-rinse” sanitizer and it works with a concentration of 70-80 ppm compared to 100ppm used for chlorine based sanitizers ( we use Sodium dichloroisocyanurate) . The peracetic acid sanitizer can affect the taste and smell compared to hydrogen peroxide based products which requires no rinse as claimed by the supplier after sanitization and it is stable at temperatures 0^oC to 80⁰C (not sure of the range as I cannot re-collect), odorless, and results in no corrosion and can be re-used several times. The reason for thinking of an alternative to chlorine was due to few factors like the time, amount of water, the odour, the water pH from my experience.

I remember reading in one paper (which unfortunately I can’t remember where it was) that the hypochlorite doesn’t kill bacteria on the vegetables but keeps the water clean; it’s the turbidity of the water which actually cleans the vegetables and the hypochlorite just prevents recontamination if the water is used again

Even I have heard (not read) about the same therefore have no literatures to support.

I wonder if there is a potential for UV?

UV lights for surface sterilization & water sterilization only. Even the same with ozone which is used for water, but can pose a health hazard. Any EMS experts can comment.



Thanks to Caz and Charles for your inputs. As Charles mentioned of the use of hypobromites / hypoiodites, which I am not aware of being used in a food produce unit or treatment of water. Correct me if I am wrong.

[Charles.C]

Dear Jean,

Thanks to Caz and Charles for your inputs. As Charles mentioned of the use of hypobromites / hypoiodites, which I am not aware of being used in a food produce unit or treatment of water. Correct me if I am wrong.

The relevant product is described in link. From memory, it was approved in USA as a sanitiser for certain food products. Advantage is a stable / low-odour, crystalline solid easy to handle. Increased functionality I think is from production of hypobromite ion which is advantageously more potent than hypochlorite (I think). Disadvantage was cost.

http://www.scorecard...s...F-SOL BRAND

This article seems to describe the principle of such mixtures -

http://aem.asm.org/c...nt/10/6/538.pdf

Rgds / Charles.C

[Jean]

Dear Charles,

The relevant product is described in link. From memory, it was approved in USA as a sanitiser for certain food products. Advantage is a stable / low-odour, crystalline solid easy to handle. Increased functionality I think is from production of hypobromite ion which is advantageously more potent than hypochlorite (I think). Disadvantage was cost.

http://www.scorecard...s...F-SOL BRAND

This article seems to describe the principle of such mixtures -

http://aem.asm.org/c...nt/10/6/538.pdf

Thanks for the literature on the effect of Bromide-hypochlorite bactericides (1962). In brief, bromide versions of the sanitizer have better kill rate at minimal concentration compared to non-bromide compounds. Though the paper states the data is pertaining specifically to individual food industry and institutional applications, I am still ignorant of its usage (excuse my ignorance).

I will check out on this with our suppliers.

[Charles.C]

Dear Jean,

From memory, as one example, it was US approved as a no-rinse method for washing eggs. I had satisfactory experience with it for seafood particularly in terms of ease of handling, no idea if the claimed benefits regarding bactericidal qualities were justified or not. At that time, several years back, it was at least 10x more expensive than conventional hypochlorite methods but I guess your dichlorisocyanurate procedure is also not that cheap ?

Rgds Charles.C

[Jean]

Dear Charles,

Thanks Charles for the info. I believe very few food industries use bromide compounds for sanitizing foods products and read in a site that it is more commonly used in swimming pools & potable water as disinfecting and sanitizing agents and also in the treatment of waste water.

Please see link on “Chlorine compounds, food safety and the environment”.



http://www.p2pays.org/ref/19/18726.pdf

[Dr Vu]

am no expert in veggies but because like 3 years ago i wrote an essay on spinach contamination and this is what i found on my research for the essay.

1) some companies use chlorine dioxide- but Jean, it does have chlorine in it
2) some companies use ozone
3) a few others use UV but mostly as a 'hurdle' ( secondary and working together with another method)
4) in some facilities they use acids- but this depends on where product will be used. Apples can be cleaned with- i believe it was acetic acid if to be used for ... was it juice.. i will check. An acid-hypochlorite mixture is another one

But do further research since these all have both advantages and disdvantages

hope this helps

Vu

[Jean]

Dear Vu,

Thank you for your feedback. What iare the best methods for reducing the microbial load of internalized pathogens?

[Dr Vu]

jean,
sorry for late response, had not realized you had asked a question

Thats a tricky thing to do since the material actually shields the microbes. If you suspect contamination of an internal nature they you need to discard the product.

[Jean]

Dear Vu,





The topic on treatment for internalized pathogens was being discussed in 235th national meeting of the American Chemical Society. The topic on “Does internalization of pathogens occur in fresh produce during commercial production & processing” was discussed in International Association of Food Protection 2008. The pathogens gain entry into the veggies / fruits through leaves, floral tubes, roots or any defects or punctures and cannot be removed by the surface washing & disinfection.



http://www.eurekaler...s-dmw031108.php

[poppysnoss]

Hi.

Yesterday I came across a bag of processed fresh carrots with a shelf life of one month. Most bags of veg etc only have a shelf life of approximately 3 days. Does anyone know what would be used to extend the shelf life but this amount? SO2? CAP, MAP???

[Simon]

Hi.

Yesterday I came across a bag of processed fresh carrots with a shelf life of one month. Most bags of veg etc only have a shelf life of approximately 3 days. Does anyone know what would be used to extend the shelf life but this amount? SO2? CAP, MAP???

Any ideas for Poppysnoss?

[ads78]

A diversion but- we use a mixing system to combine sodium chlorite and hydrochloric acid to create chlorine dioxide, which is applied through a spray bar followed by a potable rinse. As far as i am aware there is only a guideline 5ppm level on this product for application to veg. Is this correct and even very effective at this concn?

[antoni sola]

Hello,
Last year I was in a dried fruit company. I was looking for an antimicrobial for the surface contamination of the product and I found this:

http://www.ecolab.co...FST/Tsunami.asp