A few years ago, Science Friday, in collaboration with microbiologist Vince Fischetti and his lab at The Rockefeller University, conducted an experiment looking into a perennial holiday concern: will alcohol kill bacteria in homemade eggnog? We bring you the results. Please note: the sample size in this study is rather small, a single batch of nog.
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IRA FLATOW, HOST:
Flora Lichtman is here with our Video Pick of the Week. Hi, Flora.
FLORA LICHTMAN, BYLINE: Hi, Ira. We're going to have to switch gears here - big time.
LICHTMAN: The Video Pick of the Week is not particularly about a healthy thing. This is about holiday decadence. So...
LICHTMAN: ...change your - turn your monitor around.
FLATOW: Deep breath - deep, cleansing breath.
LICHTMAN: Yeah, exactly. Cleansing breath. Exactly.
LICHTMAN: So this story dates back five years, now, if you can believe it. Five years ago, we wondered whether a perennial holiday quandary, will alcohol in my homemade eggnog kill salmonella if that salmonella happens to get in there? Because eggnog is made - if you don't use pasteurized eggs, it's made with raw eggs. So there's a chance that you could get Salmonella. So we wondered: but what about if you spike it with rum or bourbon, or whatever you choose, will that kills the bugs? And five years ago, we encountered a Christmas miracle.
FLATOW: A Christmas miracle.
LICHTMAN: I think so.
LICHTMAN: Because it turns out there was a lab at the Rockefeller University, Vince Fischetti's lab, that happened to have been making eggnogs for 40 years - a microbiologist.
FLATOW: What a coincidence. Serendipity.
LICHTMAN: Absolutely. So this is a very festive lab and we asked if they would look into this and they did, several times over, for us. And so we have the results on Video Pick of the Week is originals of our sample size of one - we should be clear - experiment into this.
FLATOW: Right. And you found that if you out enough - spike your eggnog enough, should we...
LICHTMAN: Well, yes. So you can go to our website for the recipe. But after - the key to this, and actually, we'll have - let's have Vince Fischetti, sort of, give us a little background.
DR. VINCE FISCHETTI: The recipe comes originally from Rebecca Lancefield, who was a famous scientist in this laboratory. She initiated it, making it in the laboratory before Thanksgiving, and let it sit in the refrigerator until Christmas - and we all enjoy it for Christmas. It gets very smooth at Christmas time.
FLATOW: Very smooth.
LICHTMAN: Very mellow.
FLATOW: Mellow eggnogs.
LICHTMAN: But so as you heard, the key to this recipe is letting it sit around for weeks in the fridge, after the alcohol has been added. And what we found in this experiment - again, sample size of one - was that after weeks, it was sterile. They actually took this batch of eggnog just like the control, the one they make every year. They put salmonella in the eggnog because they're microbiologists, they have access to salmonella.
FLATOW: Which is what they do.
LICHTMAN: This is what they do, in the equivalent amount to one or 10 bad eggs or so. And they plated it out over time on these little plates. And if you put the sample on on the plate right after you add the salmonella. It looks like a lawn. I mean, the bacteria...
FLATOW: Petri dishes full of lawn.
LICHTMAN: Like a lawn. Just colonies everywhere. Then after a week, there are fewer. You still would not want to drink it. After three weeks, there is nothing.
FLATOW: Sterile. Good to drink.
LICHTMAN: Well, they didn't drink it. They didn't do the ultimate test.
LICHTMAN: And I don't blame them.
FLATOW: So it's our Video Pick of the Week. You can watch them make the special homebrew of...
LICHTMAN: Yes, of eggnog.
FLATOW: ...of eggnog and the recipe is up there.
LICHTMAN: The recipe is up there and they say the key, really - I mean, they, you know, the key to this experiment was letting it sit. It looked like - but it also does said that the key to the flavor was letting it sit. Now, we have like doctors who are just on the line. I'm sure they would not recommend this. And we aren't either. This is in the interest of research and science, that they know.
FLATOW: And they need to do this alcohol-like experiment a few dozen more times.
LICHTMAN: Well, yeah.
FLATOW: And - select which is the right kind of alcohol to put in there. Free test it.
LICHTMAN: Well, they - rum and bourbon.
LICHTMAN: But, yes, they don't suggest spiking your own with salmonella, for sure. But they also said that in the last 40 years, there have been no...
FLATOW: They've done this for 40 years...
LICHTMAN: Forty years.
FLATOW: Without a bad batch.
LICHTMAN: Well, they have an ad of the salmonella for years, but they'd never had a bad batch in 40 years making it in the lab.
FLATOW: Wow, that's longer than - yeah.
LICHTMAN: I mean, it's a whole lot of data.
FLATOW: Yeah. Well, there you have it. It's our Video Pick of the Week up there on SCIENCE FRIDAY on our website at sciencefriday.com. Also, you can download it on YouTube a little bit later once we get it up there. And there it is. Flora, thank you very much.
LICHTMAN: Thanks, Ira.
FLATOW: A little bit of holiday cheer. That's about all the time we have for our program. Transcript provided by NPR, Copyright NPR.