Validating my vessel cleaning method

All,

I developed a cleaning method for our production vessels.  Our production staff did a cleaning of one of our vessels via the method, a 2000 gallon pressure vessel.  I collected an initial rinse sample, then the vessel was cleaned per the method with an alkali cleaner, then a final rinseate sample collected.  I had the samples tested for HPC, Total coliform, and E. Coli.  The initial rinseate sample came back positive for Total coliform (little scary), and was > 5,700 cfu for HPC.  The final rinseate sample came back negative for E. coli and Total coliforms and 28 cfu for HPC.  I would have done a swab (think this would have been better than rinseate), but to get into the kettle to do a proper one would require a Confined Space training and permit, which none of us have.  Also, the rinseate was collected after use of the alkali cleaner but before use if the sanitizer. 

Questions:

1)  Is the testing I'm doing valid?  Is there another way that's better?

2)  Should the final rinseate sample been collected after the sanitizer?  The method does call for a sanitizer to be applied after use of the cleaner. 

3)  Am I using the right test to validate?

4)  How many cleanings do I need to do and samples I need to collect to prove I have validated?

5)  Is the final rinseate reading OK?  Do I need a final reading of 0 cfu? 

Any input would be greatly appreciated.

Thanks,

Gary

I would check AFTER the use of the sanitiser as the sanitiser is usually the KILL phase.

The results that you are looking for depend on the type of foodstuff that you are working with. Is it High risk or low risk?

Also what are the organisms of concern here? Bacteria, mould, other?

This is a fruit and vegetable coating that we're dealing with, so it's low risk from a microbe standpoint.  To produce, the coating normally is cooked at high temperatures, at least 145⁰F for 1 hour (usually higher) and has a high pH, above 8.5.  The organisms of concern would be E. coli, salmonella, and listeria.

Hi hackalot,

145degF doesn't sound so high. "cook" seems a little flattering ?. The residual cfu maybe relates to the amount of deposit / condition

 How is the 5700cfu related to the internal surface area ? swabs measure cfu/cm2 of surface, for example

_Charles,

_{Unfortunately, the configuration of the vessel makes swabbing very difficult.  In order to get a swab sample, I would have to get inside the vessel, which would require a Confined Space Permit, which we don't have.  Nor do we have the equipment to get into the kettle.  That's why we are obtaining rinseate samples.  Not sure if rinseate samples will provide the information I need or if swabbing is the only valid way to obtain the information I need to validate.  If I need to swab, then it gets real tricky.}

_{Our HACCP plan says Salmonella, E. coli, and Listeria are organisms of interest.  However, does this mean I need to be testing for them, or is testing for indicator organisms sufficient?   This is what I've been testing for in rinseate samples.}

_{As for the cook temperature, I do have literature that this would be sufficient for lethality of Salmonella, given it was for a minimum of 4 minutes.  In order to create a product, we need to cook for about 90 minutes.} 

_Gary

_{Hi gary,}

_{Regret my knowledge of in situ tank cleaning is limited.}

_{It obviously has similarities to CIP.}

_{i suspect you may be better initially served by using simpler/faster cleaning criteria followed by micro sampling but it may relate to yr detailed process.}

_{From a quick look in literature, the typical approaches seem more inclined to use pH (tests absence cleaner) and ATP (tests absence of organic material). Other non-micro variants are also used (see below).}

_{As I think you already appreciate, the key initial step is to define yr criteria(s) for validating the cleaning.}

_{I have attached examples of use of ATP, TOC, general CIP below. The 2nd is perhaps too specialised for yr situation but illustrates some of the factors which may be involved.}

The options may relate to the specification/compliance of micro. quality of yr finished product

_{Regarding cooking, 4minutes at ca. 60degC sounds improbable to me to achieve a 6D reduction but it depends on yr specific data}

tcv1 - ATP Tank Cleaning Validation.pdf   512.85KB   39 downloads

tcv2 - TOC tank cleaning validation.pdf   216.73KB   33 downloads

tcv3 - CIP procedures.pdf   507.42KB   38 downloads