- Location
- Wormingford, Essex
A question for anyone doing this, as the local EHO doesn't know....
What testing do you do to verify your pasteurisation process?
What testing do you do to verify your pasteurisation process?
I have, they don't know, and as I'm the only person asking this question in their area, I've so far been ignored.Ask the EHO
Our EHO gets us to send pasteurised milk samples on a monthly basis to Porton Down for alkaline phosphatase test. When preparing samples for this it is important to get the cooling of the sample done correctly, maintain a cool chain to the lab which must be reached in a limited time span. The enzyme which is tested for will regenerate over time, and we have had occasional "fails" when the sample has not been analysed in time (despite the logs showing it was received on time). We have driven samples to Meadow Foods in Peterborough who do this test on a routine basis for their own products, and despite failing the EHO test it has passed easily at Meadow Foods. We are very grateful to them, as they have no method for charging for the test so did it free of charge.I have, they don't know, and as I'm the only person asking this question in their area, I've so far been ignored.
Sorry, I thought you wanted to get some ideas and the EHO didn't know of your plans.I have, they don't know, and as I'm the only person asking this question in their area, I've so far been ignored.
Our EHO will only take results from the official labs. They get worried if the values are around 100, but the legal limit is around 300 (my wife looks after the detail). We work under the Specialist Cheesemakers Association Code of Practice. Samples must be analysed within 24 hours of pasteurising.Thanks @sjt01. I think your EHO is a bit more switched on, I'm told that the raw milk producers up there get most of their sampling done by the council and paid for by them too. I'd read up about the alkaline phosphatase testing but it said it needed doing immediately after pasteurisation, I wasn't sure how immediate they were suggesting. I send my other milk samples to NML, I post them in the afternoon and they are there first thing the next morning so might be quick enough? NML have two phosphatase tests listed, a biochemical test and a spectrophotometry test. Do you know which one I should do and how to interpret the results?
It is basically a test of whether the pasteurisation has been adequate (time and temperature) to inactivate the enzyme, purely as an indicator of effectiveness, not because the enzyme is important in its own right.I find this thread very interesting. Can you explain then need for/interest in alkaline phosphatase testing in milk destined for public consumption? Salmonella and listeria etc I can understand. I only ask because in my day job we measure ALP as a screen for liver and bone metabolism.
It is basically a test of whether the pasteurisation has been adequate (time and temperature) to inactivate the enzyme, purely as an indicator of effectiveness, not because the enzyme is important in its own right.
We sent cream sample and passed and was never questioned. There’s a lot of reading in your article, can you abbreviate it ?Never send a cream sample for a phosphatase test. It will probably fail
The attached report explains why & is useful to have on file if you get a new EHO who you need to "train"
Alkaline Phosphatase Levels in Pasteurised Cows Milk and Cream
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Pasteurization is built around killing tuberculosis. TB being the hardest common pathogen to kill, and the one that was most important at the time pasteurization was introduced. TB in slaughtered cattle have averaged less than 20 annually in the US for the last twenty years, I assume transmitted from humans mostly, but still TB is the standard. Alkaline phosphatase is a good indicator, maybe an easy to test indicator also?It is basically a test of whether the pasteurisation has been adequate (time and temperature) to inactivate the enzyme, purely as an indicator of effectiveness, not because the enzyme is important in its own right.
From what I understand, the enzyme the alkaline phosphatase is testing for is denatured at just above the temperature and time that tuberculosis is killed at, which is why it is used as an indicator of sufficient pasteurisation.Pasteurization is built around killing tuberculosis. TB being the hardest common pathogen to kill, and the one that was most important at the time pasteurization was introduced. TB in slaughtered cattle have averaged less than 20 annually in the US for the last twenty years, I assume transmitted from humans mostly, but still TB is the standard. Alkaline phosphatase is a good indicator, maybe an easy to test indicator also?
Pasteurisation protocols were changed in the UK a few years ago to give better kill of Johnes. TB still a big issue in the UK though!Pasteurization is built around killing tuberculosis. TB being the hardest common pathogen to kill, and the one that was most important at the time pasteurization was introduced. TB in slaughtered cattle have averaged less than 20 annually in the US for the last twenty years, I assume transmitted from humans mostly, but still TB is the standard. Alkaline phosphatase is a good indicator, maybe an easy to test indicator also?
I'm sure badgers aren't a problem in the good old US of A thoughPasteurisation protocols were changed in the UK a few years ago to give better kill of Johnes. TB still a big issue in the UK though!
Some thoughts from my wife on the test:From what I understand, the enzyme the alkaline phosphatase is testing for is denatured at just above the temperature and time that tuberculosis is killed at, which is why it is used as an indicator of sufficient pasteurisation.
We pathogen test our Raw milk anyway and that passes, so using them as an indication of pasteurisation wouldn't work.