Coliform growth in Ice cream mixes during machine stoppages

Good Evening to all,

Hope you can help me on my study regarding the acceptable retention time of Ice cream mixes in the tanks during machine/filling stoppages.
Any suggestion on how can i validate the mixes retained in the tanks on possible microbial growth specifically Coliform Growth.
We used to analyze the retained Ice cream mixes for Titrable Acidity (%TA) and temperature for us not to discard the mixes after 3 hours retention but results shows that passed results in TA and temperature will not guarantee the absence/presence of coliform in the finished product. Any suggestion as to how can we ensure that Mixes retained cannot be favorable for coliform growth?

Thanks,
kiss_lee

Hi kiss_lee,

Difficult Question!-to which I don't have an answer...but.....I think would be looking to ensure that the e-coli was not present in the mix- rather than trying to make the mix unfavourable for it's growth!!,

So looking at your PRP's eg approved supplier, Cleaning and Personal Hygiene and the effectiveness of the pasteurisation process(if any)

Regards

Mike

Thanks Mike,

During our manufacturing of ice cream, there were times wherein our Ice cream mixes (batch mix) were retained in the tanks due to machine stoppages/ malfunctioning, mixes which are to be filled stayed in the tanks resulting to temperature fluctuation which may results to fermentation that may be an indication/ favorable for microbial growth, my question is, do you have any idea on how long this mixes can stay/retain in the tank which can ensure the absence of coliform. Or do you have any related study regarding coliform growth in Ice cream mixes?

I really appreciate your response Mike.


Thanks,

kiss_lee

Thanks Mike,

During our manufacturing of ice cream, there were times wherein our Ice cream mixes (batch mix) were retained in the tanks due to machine stoppages/ malfunctioning, mixes which are to be filled stayed in the tanks resulting to temperature fluctuation which may results to fermentation that may be an indication/ favorable for microbial growth, my question is, do you have any idea on how long this mixes can stay/retain in the tank which can ensure the absence of coliform. Or do you have any related study regarding coliform growth in Ice cream mixes?

I really appreciate your response Mike.


Thanks,

kiss_lee

Hi- I will have some stuff somewhere-which i'll try to dig out for you

the point i was making in my previouds post though- is that if you eliminate the e-coli in the mix - there will be none there to multiply -whether the conditions are favourable for multiplication or not!!- IMO always best to eliminate the hazard, rather than try to control it?
Regards

Mike

thanks again mike..i will wait for your response mike..hope you'll find that stuff the soonest...thanks a lot..





kiss_lee

thanks again mike..i will wait for your response mike..hope you'll find that stuff the soonest...thanks a lot..





kiss_lee

Hi there are some nice growth curves on page 4 of attachment (on beef though!) at 4-30 degrees c

Also thought you might be interested in this link Optimal Growth Conditions e-coli

The other document is the New Zealand Ice cream Code of practice- which is from 2003-but is probably the most comprehensive resource on ice cream safety i've ever seen! (170 pages of haccp lovliness!)

Regards

Mike

Dear kisslee,

Apologise for my ignorance of dairy product but is the step you are referring to before or after pasteurisation?. (i guess the former based on flowchart in Mike's attach.)
Not my product area at all but, if before pasteur., undoubtedly Mike’s suggested logic of removing coliform inputs is critical although I noticed that the NZ attachment repeatedly suggested the avoidance of setting up CCPs for receiving goods, an implicit acknowledgement of the difficulty perhaps? Whatever, actual data will probably be necessary in addition to the magic COA. I expect you hv such already ? Nonetheless, I presume the pasteurisation step will eliminate coliforms quite efficiently within it's design level. If after pasteu., the equipment etc obviously triggers in.

The kind of scenario you are looking at seems to conceptually have similarities to predictions of max. haccp storage times for chilled finished products, or perhaps even semi-finished items – these are often based on criteria such as”maximum x generation times such that the level of a defined species, eg L.mono, will not exceed Y cfu/g”. Software programs hv been used for above for many years for pathogens, but coliform no idea. Mikes first attach. is a (high-powered) deliberation on such things.

The item somewhat missing from yr posts is experimental data, eg what the current situation actually is like with respect to coliform ?. I presume you run control charts as in Mikes attach.? I appreciate that you may prefer to primarily run on quick feedback data rather than micro. but for validation purposes, probably no choice but to collect. This is illustrated in Mike’s amazing 2nd attach.

I daresay you hv done all the above thinking already !?

Rgds / Charles.C

PS, after noticing Mike's comment earlier, i presume there is a pasteurisation ??