A Concerned Scientist @BE@qoto.org

@CdnCurmudgeon

I have to admit that I thought I'd done a pretty thorough review of relevant papers, but this 1953 one referenced in the article was not on my list.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1791522/?page=1

@samhainnight

Also, I just don't know about UHT in this scenario. They didn't test any higher temperatures in this test, and from what I understand it's only for ~2 seconds. It would be interesting to find out, though.

@samhainnight

If, and this is still an if to me, high temperature short time pasteurization really is the standard, then what I found was the procedure there is "heat the milk to between 72°C to 74°C for 15 to 20 seconds."

If that's what's being done currently, then this seems to show that it brings the amount of detectable virus below detection limits, but, there is enough live virus to replicate when inoculated into chicken eggs.

From there, it does still go down further when refrigerated over time, but also does not go away.

Between the two, is that enough to make certain that it's not enough to make people sick? I don't know, and I don't know if there's a known infectious dose that we could go off of to do that calculation.

@kateiacy

That's the way I understood it, basically, but I've been told more than once that different facilities may have slightly different procedures, and I'm honestly not sure how that works.

Earlier today I read that all of these are acceptable:

Batch pasteurization: Also known as low-temperature long time (LTLT) pasteurization. Heat the milk to 63°C for 30 minutes.

Flash pasteurization: Also known as high-temperature short time (HTST) pasteurization. Heat the milk to between 72°C to 74°C for 15 to 20 seconds.

Ultra-high temperature (UHT) pasteurization: Heat the milk to between 135°C to 140°C for 2 to 4 seconds.

@anarchademic @PacificNic @noyes

It has been airborne between mammals previously, yes.

If you want to dig into it, I have some stuff further up in this thread:

https://qoto.org/@BE/112474268703528800

https://qoto.org/@BE/112327895801309084

@noyes @PacificNic

Both my fear and my hope early on were that it if there was already H5N1 out there, that it was "indistinguishable" from COVID in that people were getting sick and either not testing, or getting negative COVID tests and assuming it was actually COVID. The hope being that then it was clearly not 50% fatal.

@Infoseepage

State's rights.

Because the cows don't die, I think there's an underlying belief that if they let it run its course enough antibodies will be in herds that it'll "go away." To be fair, if the influenza A spikes that have been seen in wastewater were from animal sources, as some have said, they seem to have peaked around May 8th. I'm certainly not predicting it's all on the down swing from there, but, I suspect that's the hope in some circles.

For whatever reason there seems to be a lot of H5N1 science in the news today. Since I haven't been keeping up, here's a bit of a summary of what I've seen.

When the FDA tested milk samples from stores, the original numbers to come out were kind of vague. Eventually they released them all and 20.2% of 297 samples, from 17 states encompassing dairy from 132 processing locations in 17 states were positive for H5N1.

https://www.fda.gov/food/alerts-advisories-safety-information/updates-highly-pathogenic-avian-influenza-hpai#testing

This answered a lot of my early questions. I'd even reached out to an acquaintance who was a purchaser at a grocery chain to try to figure out how milk travelled around the country, but now we have some details. To me, this means the outbreak is a lot bigger than 51 herds in 9 states, which, to be fair, was obvious. But, now that we're talking bigger numbers, let's zoom out to the whole country. There's upwards of 10 million dairy cows in the US. While I am *not* talking about H5N1 being everywhere, I think the possibility exists that we are saying that millions of cows may have been/are infected.

I posted elsewhere today that what we *know* of in terms of spread is mammal to mammal transmission amongst herds of cattle. I do think that accounts for 51 herd in 9 states. However, if we're talking millions of cows, and I'm not sure that we are, we just haven't tested enough to know, then we're likely talking about birds spreading H5N1 across state lines from herd to herd. Unproven, but, keep it on your radar.

Next up, raw milk and pasteurization. Researchers from the Texas A&M Veterinary Medical Diagnostic Laboratory obtained cow’s milk samples from an affected herd in New Mexico.

https://www.nejm.org/doi/full/10.1056/NEJMc2405495#t1

First up, they "orally inoculated" mice with the raw milk. The mice were sick on day 1, and all lived until day 4 at which point they were euthanized and tested. Infection seems to have set in in the pharynx, and led to systemic illness. I don't think that's a surprise, but there you have it. Further, infections were found in the mammary glands, despite the fact that the mice were not lactating. So, similar to cows and their milk, we seem to have an influenza virus with an affinity for mammary glands.

Next, while they are clear that their bench top experiments do not exactly replicate commercial pasteurization processes, they tested heating the milk to 63C and 72C for a variety of times.

All longer times, 5, 10, 20 and 30 minutes at 63C led to no live virus above detection limits.

At 72C, times of 5 seconds and 10 seconds led to detectable amounts of live virus, but 15 seconds did not.

Further tests at 72C for 15, 20 and 30 seconds were inoculated into embryonated chicken eggs or Madin–Darby canine kidney cells for virus detection. These samples showed "educed virus titers by more than 4.5 log units but did not completely inactivate the virus."

One thing I want to highlight here is this:

"The stability of HPAI A(H5N1) virus in cow’s milk stored at 4°C is another important question. For milk sample NM#93, we detected a decline of only two log units over 5 weeks. HPAI A(H5N1) virus may therefore remain infectious for several weeks in raw milk kept at 4°C."

I've leaned towards believing that H5N1 wouldn't survive long term in milk, but, that's why I try to avoid prognosticating as much as I'm able to. I was apparently wrong about that.

So what does all of that mean for milk at the store? I don't know! We'd have to establish an infectious oral dose to know whether what *could* remain after pasteurization, and refrigeration, is significant.

I have other thoughts, but, that's enough of a novel for now!

In terms of institutional support, I was working at a national lab at the time. By rule, I had to disclose to them that I was visited by law enforcement. I did so, explained the whole situation, and no one cared.

https://www.nature.com/articles/d41586-024-01468-9

I'm really glad to see this phenomenon getting some attention, and I'd like to point out that it's nothing new, and it's really not that uncommon, unfortunately. Social media has just made it much easier, and seemingly more acceptable.

A long time ago, back when cameras on phones were new and rare, one day I was home visiting my mom. We noticed a man and a woman going door to door in the neighborhood knocking on doors, filming the neighbors talking. They skipped over our house, and were at another neighbor's house when I went out to my car. They ran over to me, got in my face, and started asking me questions about research I had done that outed a particular polluter of a waterway.

My reaction was....not the best. I wasn't prepared for it at all. I got in my car, started it up, and threatened to run the woman over when she got in front of my car and wouldn't let me leave. I didn't run anyone over, but, I did get a visit from the cops. Thankfully she had relented after a short standoff and let me drive away, and no charges were pressed either direction.

Refer back to this anytime you might wonder why I don't use my name online.