Thermophilic & Mesophilic Bacteria & Spores
Hi all,
I'm at a complete loss and desperate for any information anyone can supply as the internet is failing me on this one.
We buy and sell dairy powders and quite often will buy powder which has been downgraded from UHT to a standard spec due to higher thermophile & mesophile levels. My problem is I have no idea what would realistically be a "safe" level. I understand that these tests are generic so it would be dependant on the specific strain(s) of bacteria giving the higher levels, but I also know that these types of bacteria are pretty common in the standard grade milk powders, they're just not tested for.
I'm looking for any information on safe and unsafe levels of Thermophilic and Mesophilic bacteria and spores (not bacteria specific), specifically in dairy but any information would be useful.
Kelly
Hi Kelly,
I assume by "safe" you mean as in "FS" ?
Dairy/UHT not my area of expertise but I presume there is a specific reason for the "downgrading" you refer to ? is it supposed to be safety-related ? or perhaps spoilage potential, ie shelf life ?
Offhand, yr query sounds analogous to another old FS chestnut - What is a safe level for APC ?
IMO it's unanswerable without involving specific microbial context.
"specs" include both safety and non-safety microbial limits.
Hi Kelly,
I assume by "safe" you mean as in "FS" ?
Dairy/UHT not my area of expertise but I presume there is a specific reason for the "downgrading" you refer to ? is it supposed to be safety-related ? or perhaps spoilage potential, ie shelf life ?
Offhand, yr query sounds analogous to another old FS chestnut - What is a safe level for APC ?
Just to give a little more context, the product has been downgraded as it's no longer suitable for infant formula applications but is deemed safe for general consumption. As it was manufactured to a higher spec and failed to meet that spec it is considered downgraded product. With the exception of thermophile counts there is no other issue with the product.
Safe levels is probably not the right phrase. I'm not sure about other countries but in FSANZ code there are limits for APC/SPC for different types of dairy which is basically the level of "this is just too risky, don't sell". That's basically what I'm trying to find here. At what level for thermophilic bacteria and spores would you say 'this is way too risky, not suitable for human consumption.
Hi Kelly,
You may be correct in that the Australian Dairy Industry has a different micro. interpretation for HACCP purposes as compared to other Australian Foods.
For example here is a quote from Micro. Criteria - Food Standards Australia New Zealand 2016 -
MAB (mesophilic aerobic bacteria count) is one of the most common tests applied to indicate microbiological quality of food. It does not determine the presence of pathogenic microorganisms and should not be used as a direct assessment of safety.
Can compare above to this quote from Dairy Processing Standard (Australia only) 2008 -
For microbiological hazards the acceptable level may be specified by the dairy processor. Such levels may include a total plate count (BactoScan Count) or bulk milk cell count, which may be calculated on a daily, weekly or monthly basis.
I noticed some dairy grading levels based on thermoduric levels in the attached current dairy manual from Food Standards ASNZ website which may be of interest but i daresay you are familiar these already. Not safety related afai can see.
risk profile dairy products in Australia.pdf 3.51MB 46 downloads
Hopefully other posters may have some specific Dairy knowledge to assist. Good Luck !
There are very few thermoduric spores that can be a food safety issue. The reason there are limits for infant formulas is because of the higher risk infants have as compared to other groups of people. Infant formula has very low tolerances for a lot of things.
FYI...
Thermophile – bacteria with relatively high optimal growth temperatures, usually between 40o C and 70o C, that do not grow well at mesophilic temperatures.
Thermoduric - typically spores that survive high heat. This is the main concern.
The one spore that comes off the top of my head is C. Perfringens which develops spores, but itself is not a pathogen. It however, produces toxin when it is in an environment that provides suitability for growth of the organism.
This may come in handy to better understand...
http://www.fda.gov/d...k/UCM297627.pdf
I have experience in dairy powder, NFDM and Buttermilk, manufacturing, but I wasn't involved in the export of these powders so I can't speak on what the requirements are for Australia and New Zealand. In the US, there is regular testing and grading of dairy powders based on their results. The powders can get downgraded if bacterial levels, including thermodurics, are too high. This was 15 years ago, so I can't remember what the limits were...sorry. It may help to do some searching for US Dairy Grading. There is a section on dairy powder grading.
I hope that helps.