Brucella virus and raw milk

[AnnDee]

I hope you all can help me on this.

So the local goverment decided we cannot have raw milk anymore because of the Brucella virus that might exist in unpasteurised milk. I know that the cattle that I got my raw milk from has been vaccinated but it is still against the law to use raw milk for now. My question is, will the thermisation process (instead of pasteurisation) kill off the virus? Is fermented dairy products like yoghurt can be considered safe? Does the fermentation/culturing kill off the bacteria?

[Duntov]

I did find information on this subject that I have attached.  But not being the scientific type, I am not sure how to interpret the article.  Perhaps Sailor could chime in on this topic.

[awakephd]

I'm not sure exactly what thermisation involves, but I'm wondering if it is what I would call Low Temperature Pasteurization - 140°F / 60°C for 30 minutes. If so, my understanding is that this is considered to be pasteurization ... but I don't know if it kills all possible viri or bacteria ...

[Sailor Con Queso]

There are several species of Brucella that cause "Brucellosis" aka Undulant Fever. This organism was the primary rationale for pasteurization worldwide. In the USA, aggressive vaccination programs and pasteurization have made the disease very rare with just 100 cases last year. But it took many decades and several generations of cattle to control the disease. It has been completely eradicated in some European countries, but is still endemic in others. In Indonesia, it is still a very high risk in raw milk, so the local government is just trying to protect you (and everyone around you).

Optimum growth temperature is 37c/98.6f (normal human body temperature). Lab tests for lethal temperatures - 2 hours at 55c/131f, 15 minutes at 60c/140f, or just 5 minutes at 65c/149f. So low-temperature pasteurization would be effective (if allowed by your local government). Some sources suggest that meat must be cooked to 63c/145f to be sure Brucella is completely killed. So much for medium rare steaks - generally cooked to around 57c/134f.

[Duntov]

^^^Good information right there.  And next time I go to Malaysia, my steaks will be cooked at least medium well.   

[AnnDee]

Thank you all! I am so glad I'm in this forum with you all.

There are several species of Brucella that cause "Brucellosis" aka Undulant Fever. This organism was the primary rationale for pasteurization worldwide. In the USA, aggressive vaccination programs and pasteurization have made the disease very rare with just 100 cases last year. But it took many decades and several generations of cattle to control the disease. It has been completely eradicated in some European countries, but is still endemic in others. In Indonesia, it is still a very high risk in raw milk, so the local government is just trying to protect you (and everyone around you).

Optimum growth temperature is 37c/98.6f (normal human body temperature). Lab tests for lethal temperatures - 2 hours at 55c/131f, 15 minutes at 60c/140f, or just 5 minutes at 65c/149f. So low-temperature pasteurization would be effective (if allowed by your local government). Some sources suggest that meat must be cooked to 63c/145f to be sure Brucella is completely killed. So much for medium rare steaks - generally cooked to around 57c/134f.

Thank you Sailor, low temp pasteurisation it is then. Hopefully it doesn't change the taste of the cheese.
Thankfully I eat my steak medium (pink in the middle) only. 

^^^Good information right there.  And next time I go to Malaysia, my steaks will be cooked at least medium well.   

Don't worry, we normally get our steak meat mostly from Australia, also some from NZ and USA (Angus). The local beef is normally cooked into some other dishes that require long cooking (the meat can be quite tough I can tell you that).

[LantGladstone]

Sailor seems to have nailed it. 

If you do need a source and happen to be down here (and have a cooler for the ride back) I know a source of both cow and goat in S'pore.  I assume there wouldn't be an issue at the Causeway.

[AnnDee]

Sailor seems to have nailed it. 

If you do need a source and happen to be down here (and have a cooler for the ride back) I know a source of both cow and goat in S'pore.  I assume there wouldn't be an issue at the Causeway.

Thank you! I might take that offer on the goat's milk soon!

[AnnDee]

Hi all,
What do you all think about this:
http://www.bbc.com/news/world-us-canada-39229635

Is listeria still exist in a cheese after 60 days aging? Or it can only be eliminated by pasteurising?

[Gregore]

I find it interesting that the article felt the need to mention that the company founder originally started out making cheese at home .  Like that makes a difference all these years later with why people got sick.

Also how many people died in accidents driving to whole foods that day to get groceries .

It was not mentioned becuase there are not enough hrs in the day to write articles about all the car deaths , because it is so common .

I now take most dangers the media speak about with a grain of salt , because if it was really that common they would not report it . They report things that are statistically rare and  unlikely to happen and make you feel like you are in danger .

[SOSEATTLE]

Is listeria still exist in a cheese after 60 days aging? Or it can only be eliminated by pasteurising?

Listeria is extremely common in the environment. It is killed by pasteurization, however, if the milk is re-contaminated by Listeria on equipment or other environmental areas of the cheese making/aging rooms then it can still cause illness. The best way to control it is proper sanitation at all steps in the cheese making process from milking to finished cheese.

Susan

[Sailor Con Queso]

http://www.bbc.com/news/world-us-canada-39229635 Is listeria still exist in a cheese after 60 days aging? Or it can only be eliminated by pasteurising?

First of all, note that "Officials say it was probably caused by a soft raw milk cheese ..."

Soft or fresh cheeses are MUCH more susceptible to all sorts of contamination, including Listeria. The milk itself might be contaminated, especially if using raw (unpasteurized) milk. The cheese can also be contaminated during the make or handling afterwards. In either case it is important to understand that refrigeration does NOT completely protect the finished cheese. In fact, Listeria does just fine at refrigeration temperatures and ironically is suppressed at room temperature. While it is very possible to make soft/fresh cheeses from unpasteurized milk, that is not a risk that I am willing to take in my commercial operation.

Aged cheeses are not entirely immune even if aged 60 days or more, but good sanitation and manufacturing practices eliminate most problems. And there are a number of bacteria available that produce Niacin, a natural antibiotic, that prevents Listeria in aged cheeses.

Deaths from Listeria are actually rare but can be especially dangerous to those with weak immune systems, older people, pregnant women and children. Doctors often tell pregnant women not to eat cheese (which is a really stupid thing to say). What they are really concerned about is Listeria in fresh cheeses, which can cause spontaneous abortion.

[AnnDee]

Thank you Gregore, Susan and Sailor!
Thank you sooo much.
I have been so worried with this, I am too scared if anyone get sick or worse because of my cheese.
My heart goes for the victims but I also feel bad for the creamery.

I did avoid eating soft gooey cheeses while pregnant but still ate hard cheeses. Normally I was feeling too sick to eat soft gooey cheese anyway.
Sailor, can you advise the bacteria that produce Niacin? Is this a special bacteria?

[Sailor Con Queso]

It is not just the species of bacteria, but also the strain. These fall under the category of adjunct bacteria, which can also affect flavor & aging profiles, so you should discuss this with your supplier. In the states I would talk to Dairy Connection. In Canada (or the States) I would talk to Glenngarry Cheese Supplies.

Again, just to clarify, Listeria is generally not a problem with aged cheeses. When it does happen it is always because of poor sanitation and/or sloppy procedures.