Hello and welcome to cooking issues. This is Dave Arnold, your host with cooking she's coming to you live from newsstands Rockefeller Center joined as usual with the Stasi of the hammer Lopez how're you doing? Good. We got John John in the booth. How you doing? Doing great. We got where Jackie molecules. Where are you? Where are you right now? I'm in DC now DC Geez man, what's up globe Hopper just like everywhere. You're like a like a like globetrotting trotting engineer. Yeah. And of course, yeah. And of course, working the panels, Joe Hasan is doing how are you doing? Doing? All right. And for those of you who are listening, live on Patreon call in your questions. 2917410 1507. That's 9174010 1507 And I anticipate you might get some calls in because today, we have a very special guest. Professor Don Schaffner, who is the extension specialist in food science and distinguished professor at Rutgers, a host of the podcast podcast is called riskier not correct. That is correct. Risky or not, which is a good which is like a good thing. Because it's not like completely safe or not. It's risky or not. In other words, like, Should I do this? Or should I not do this? Right?

Exactly. That's the premise of the show. Yeah.

And we'll get into that in a little bit. And on the Twitter's you go as bug countered. Now, let me ask you a question. Do you legitimately like sit around and do counts all day?

Graduate students for that?

Yeah. So you're more like bug counter overlord?

Well, so So here's the thing. So I describe myself as a quantitative food microbiologist, and I ascribe to the the adage, when you can count and so I do, I do like quantitative data. And so we work with micro organisms. And so bug counter became my my name on Twitter. I do want to say for the record, I don't count. Nobody in my lab counts insect parts. And so I'm using bug there in the colloquial you know, as microbiologist refer to the organisms we study as bugs, but not actual, literal anthropological bugs.

So you're not at all worried about like number of cockroach legs in my in my flower, for instance.

Well, I you know, cockroach legs won't hurt you. It's the it's the micro organisms on the cockroach like Sybil hurt you. And so yeah, it's gross. It's disgusting to have cockroach legs in your flower, but that the cockroach legs? You know, they're not they're not big enough to actually stick in your throat and hurt

you. I mean, it seems a little bit like, guns don't kill people kind of an argument is not the cockroach legs per se. It's the fact that they walked through poop before they showed up in your food.

Well, let's see. Like, not to stretch the gun analogy. But if you had a gun without bullets, I guess you could throw some throw it at somebody. Right? You know. So I mean, if you have sterile cockroach legs, you know, it's gross. But sterile cockroach legs? Don't tell you it's microorganisms.

But before I get into the why I actually had you on I'm curious about this. You know how back in the, in the early 1900s. Right, when people were going through their first wave of getting really, really worried about kind of germs and insects and whatnot. And everyone was like, Oh, my God flies fly. Oh my god. Right. But flies legitimately do land in filth and then land on your food? Right? I want to make a t shirt for flies that says, my last meal. My last resting place was poop. You know what I mean? So they can wear some of the land on your food. They can wear a t shirt because I was just in Bo Ryan. I mean, like, that's kind of true. Right. But there's how much actual spread? Is there via fly?

Well, this is a really good question. And it's actually a topic that has come up before on risky or not. And, and so when you think about it, again, as a quantitative microbiologist, you know, and as somebody who does risk assessment, there's an expression in toxicology, the dose makes the poison. And the same sort of thing applies to microbiology as well. And so yes, flies can theoretically spread germs. But the what you have to say you have to consider as well, where was the fly last? Okay, did they walk on poop? Did they get some, let's say salmonella on their feet? And then did those salmonella, then transfer to the food? And were the levels sufficiently high such that you have a reasonable probability of illness or is with with any salmonella transfer? And so, you know, certainly I don't advocate eating food on which flies have walked but the actual risk from a single flight landing once on your food before you, you brush it away, that's probably a pretty small risk based on all of the available scientific information, which admittedly is not is not a lot.

So you're cool Is it?

Well, here's the thing, the name of the show is not cool with it or not right? The name of the show is risky or not so gross. I don't advocate again, I don't advocate buys walking on food. I certainly if I have a choice to have wise not walking my food, I will definitely choose that. But but from from a risk perspective, again, the chance of illness from a single fly landing off a food once. I'm gonna say that's a pretty small risk. So but that's a different from I'm cool with it.

All right. All right. So in other words, you're like, I would rather it not happen, but you're still going to eat it?

Well, you know, that's a good question. I mean, I don't I don't have a I don't have food in front of me that a fly is just landed on to be able to definitively say whether I would or not. Yeah, I don't. Yeah. And that's a different question. Like, would don eat it or not? That's again, that's yet another different podcast,

we got to start that show. I gotta get that show, like, the Stasi and I will create various levels of gross and handed to you and be like, did he eat it? Well, just you don't even have to say anything. It's just we have the camera on you. And then like an hour later, we'll look and if you took a bite out of it, it was fine. I mean, or you decided to eat it. Just an idea for you. You don't have to deal with us if that idea is yours. Yeah.

But um, here's the thing, we should also have, like a revisiting, like, come back 2448 72 hours and see if I had any consequences from eating it. Right? Because that's the important. That's the important thing.

Oh, you know what, before we even get into what I wanted, let's talk about this. Because this is a big deal for all human beings everywhere. It is my feeling. And you tell me because I'm happy to be wrong about this, that nine times out of 10 people have no idea where they got their food poisoning from but they think they do. And so they blame X, Y or Z thing. But they're very often wrong, because they don't really have the incubation periods. Right? You want to talk about this at all, whether I'm wrong or whether what you think about it.

No, no, I think you actually, I really appreciate you raising this this point. So very often people will think it's the last food they ate, which for certain types of foodborne disease might be true. But for many types of foodborne disease, it's absolutely not true. And it's more likely something that you ate 24 hours ago, 48 hours ago, even as much as 72 hours ago, three days ago, and so yeah, people will very often get that wrong. For sure.

And is it the salah that kills you? Nine times out of 10? Is it the salad?

Oh, it depends. It really depends. I mean, we are in we are in the risky salad season. If you look historically, at when people get sick from eating leafy greens, often it is around this time of year. And so it is there is some some potential risks, but it might be salad it might be it might be you know, meat that was cross contaminated. It might be undercooked meat, it might be food that was left out or temperature control for too long. The problem. The problem with microorganisms, you know when it comes to food is that they're they're so diverse, and there's so many different ways they can cause illness. So it's it's difficult to generalize and say, oh, yeah, it's the salad. Because sometimes it might be the shell, but sometimes it might not be

I did not know that there was a risky salad season. But now I'm kind of grooving on the idea of a risky salad. When is Doctor done? When is the risky salad season?

Well, it's roughly this time of year. So it's it's roughly in the in the fall like I would say September October. You know that timeframe. But But again, that doesn't mean that other it's like it's like when you eat shellfish or right in months, months. You're only supposed to eat shellfish. And once women are right, but but so it's not it's not it's not a definitive indication of risk. But if you if you look at the outbreaks, and if you look at big outbreaks linked to leafy greens in particular, they do tend to happen around this time of year. But again, that's not it's again, like so many scientific things in life. If there's it's not hard and fast. It's only a general a general statement.

Is that just a non correlation or is there a theory? Is there a positive cause for that?

Well, we you know, in many cases, we cannot trace the the cause back to a specific incident, what we do know and again, this is talking specifically about leafy greens in this country. And so the leafy green industry, the way that it works is they start in California. And then as the as the season progresses, they move gradually south and end the season in Yuma, Arizona. And so we are in that period now where we're in transition from California to Arizona. And we don't know, we don't know what it is about that transition period that might lead to that might lead to outbreaks. But but it is something that a number of people have observed, but we still haven't quite figured it out. Obviously if we figured out the industry would be fixing that problem. And we wouldn't we wouldn't have this but So for now, it's only it's only a general idea. Like I said,

first of all, I feel like you can't Going out Arizona, I just feel like I feel like you were like, throwing some serious shade on Arizona right now.

Well, it might it might not be evelopment might not be arriving in Arizona, it might be aspects of leaving California, right? It might be aspects of packing up the operations, you know, and leaving California. So let's let's not let's let's let's let's throw equal shade on both chairs.

Well, you're saying not that Arizona is bad. It's just California has some salubrious effect on the on the greens to get rid of that. What's the what's the pathogen of interest here? First of all, are we talking about Romaine because it's always Romaine that they that they, they burn, right that they they sweep off of the shelves, at least here in New York, and then burn is that we're talking about?

It is it is often Romaine. But again, one, one point that I want to make is that part of the reason why Romaine may cause a lot of outbreaks is we just eat a lot of Romaine, right. And so it may it may not be that Romaine per se is risky, it may just be that, that that's just the predominant leafy green that we eat, right. And we do know that it may well be that these packaged salads are riskier just because of the way that they are prepared, you know that the lettuce is harvested, the lettuce is chopped up, it's washed. And so you're if you have contamination that may spread the contamination over multiple servings, and then also when you when you chop off that lettuce, that may lead to places where their harvest points for the bacteria. Whereas if you leave the lettuce hole as as head lettuce, the contamination may be confined to a single head and potentially, there's less cut edges of the leafy greens to allow the bacteria to attach and maybe to grow.

Now once you get your, your your whatever pathogen of interest into your lettuce, it can no longer be washed off the surface, right? Like once it's been hacked up and it's grown into the lettuce like pretty much that's it right?

You may be able to wash some of it off, but it's certainly the best thing to do is prevention, right? The best thing to do is keep it from getting there in the first place. Because once it's there, yes, you're right, it's very difficult to remove. And again, this part of part of what we're trying to do here when we're washing is we're using sanitizers in that wash water so that if you do get, let's say some pathogens that are on one leaf, they don't go into the wash water and then cross contaminate to another leaf by by using sanitizers in that wash water. You stop that stop that spread. But if it does, if it does spread then you it's going to be really tough to do anything about that.

What are your thoughts on you get the bag and they say it's pre washed, but it's already turning into its own filth inside of the bag and like clearly like slimy and garbage. And your son is like oh, it's just it's already washed. But I'm like, No, either you wash it and it like or you throw it away. This is filth. No, I mean this idea that you can wash it once and forget it. It's crazy right?

Well my sons have been trained not to have that conversation. They don't live with me. But they're grown they're grown young man but know what I will say. So if there's a there's a scientific report out there that says that basically in the opinion of experts once the lettuce is been triple washed and it's placed in a bag, there's very little additional washing that the consumer is going to be able to do to have any positive benefit and in fact it might you might actually increase the risk if you don't have good sanitary practices in your kitchen and so the the general advice is you don't need to wash pre washed lettuce because the the either the risk is not there and you're going to be fine. Or the risk is there there's not much you can do about it. But now the other point that you made about things looking gross or slimy or being past their, their, their Best Buy date, I'm pretty particular about and we do buy bagged lettuce in my house and I'm pretty particular about how it looks. And so if I do start to see, I'll pick out the slimy pieces and if it starts to look too slimy I'll just I'll just pitch it and say we need to need to go to the store and get more because I mean again it's not the slime that makes you sick but that slime is an indication that maybe that lettuce has been mishandled or temperature abused or just you know, physically beat up to the to the extent that it allows harborage points for the bacteria in places where they can grow.

It's always it's always the arugula. It's always the arugula it goes slimy and smells like an aquarium. Terrible.

You know, that's, that's funny. I've I find the opposite. I find that arugula for whatever reason is is pretty is pretty robust. Whereas the romaine and the spinach, at least in my house that tend to go to go bad before the arugula, but you know, that's just my experience has been

started bad. That's the spinach started out as bad you should be cooking that. You don't I mean, like,

Yeah, I'm not a I'm not a fan of Ross. Yeah, the point.

They're like, but if the spinach is real, real tiny, you can eat it. Okay or you could just let the Spanish get big hack it up cook it with in a cream sauce make sure you squeeze out all the nasty like filth water not because it's unsafe it just because it's filth water. You're not saying anyway. Like, look, I don't know what at some point in my, in my 30s Everyone started eating all of these formerly cooked greens raw. And I'm like, why? Like why would I ever eat kale raw? Why would I do that?

Well, I mean, I'm old enough to remember that what you bought kale for was to put on the salad bar over the ice. It was decorative. Nobody ate it.

Yeah, nobody. I mean, I had a rabbit. Rabbit would eat it. You know what I mean? But like, or kale makes a decent cooked green. I mean, it's no chard. It's no, you know, it's no collard. You know what I mean? It's not even at the level of an escrow role. You know what I mean? But it's, I mean, I shouldn't say Escrow is great. I don't know why. I don't know why I suddenly put s girl next to Kayla. This girl is delish. I grew up eating cooked Eskimo, you know what I mean? Anyway, alright. What about this? What about people? What, before we get off these bad greens? What about people who believe and this is also meats and veg, who believed that by somehow buying and you alluded to this by saying, you know, if I'm chumming up, you know, eight tonnes of Romaine and putting them into a giant vat, and then I f up somehow and put them in a bag. Now I have eight tonnes of Romaine that had been effed up by one bad head. Right that you kind of intimated that right. It's the same mark. Yeah,

I don't think the industry calls it chumming. But that's a good word.

Yeah. Well, it's the same argument with ground beef, right? Like you take, you take infinity cows, you grind them all together. And if one of those cows was bad, now, the whole batch is like, you know, it's the one rotten apple kind of a situation, right? And, well, I

think what I think of ground beef is a little bit different. But we can come back to that right law. So

now people have taken that argument. And then they believe somehow that they are safer buying, quote, unquote, farmer's market, or organic products, even though in a supermarket organic product has been there for 8 billion years, just because the turnover is so slow, at least it used to be, you know, if you're not shopping at a specific place, it only sells organic stuff. So what do you think? What do you think about people who believe that they're trying to dodge a safety bullet by going that way?

Well, you know, there's, there's not a ton of research on organic versus conventionally grown food. But the research that's out there shows that either the risk is equivalent, or that the risk might actually be higher with organic, just because of some of the growing practices, you know, increased use of manure, you know, things, things like that. And so, but it's, but again, there's very limited research. And so it's by no means definitive. But But I think if you're if you're buying organic, because you think it is safer with respect to bacteria, that's probably not true as a true assumption now, that you know, and again, the tests for pesticides on our organic versus conventional show that overwhelmingly, you know, the food that we eat in this country is free of pesticides. And so there's, there's very little difference there as well. So, I mean, I think a lot of people buy organic, just like a feel good thing. And certainly farmers can charge a higher price. And so if you want to give the farmers more money, I'm all in favor of tanking farmers more. So that's a good thing. But I think that the the effect of organic versus conventional on risk is equivocal at best.

All right. And you know what? Well, we'll take the push back later on that we'll just take the push back later, we'll leave it we'll take the push back later. So another reason I really wanted to have you on is because you know, your particular attitude, which I've noticed on Twitter, which which I enjoy and wanted, maybe you could talk a little bit about the adversarial relationship that kind of develops between cooks, and food safety people. And you know, I think it's, it's real. I know, you're not like people who I know who have been involved in writing some of the codes who I've talked to over the years, I've meet scientists and safety scientists, they're really into kind of bullet proofing, everything. And I know that a lot of chefs feel hamstrung by a lot of the rules that we have to cook by that we know are inherently inaccurate, that are basically overkill, right? So I'm specifically talking about certain classic fermentation practices that weren't available to us in restaurants for a long time. Yeah, we would get shut down, or certain low temperature practices, which, you know, were not available to us because they didn't meet the old quote unquote, food code and this kind of big adversarial relationship has developed. I wonder whether you want to talk about that.

Yeah, so this is one of my favorite topics to talk about. And so it's, it's tough, right? Because on the one hand, you have the chef's that really pretty much want to do anything. You have the code, which is written by Well, it's written by scientists and lawyers and the because what we have to do in code is we have to create bright lines that say, Thou shalt not cross this line, right? And then you have scientists like me who are like, Wow, it's really more of a fuzzy line. And it's complicated and 10s. And there's levels of risk. And so yeah, it ends up being a really interesting conversation. But one thing I am really interested in doing is pushing back on regulatory types who say, No, Thou shalt not cross this line, and then having the debate about well, okay, so tell me, tell me exactly how you decided to draw that line? And why did you draw it there? And what are the factors that you considered? And what are? What are some other mitigating factors that we could, that we could use to maybe draw that line in a different place? Or hey, you know, the logic that you use to use to draw this line means that we should also draw this other line over here, and try to use that logic and argument in a way that maybe gives the chef's have more freedom or figure out? Is that line even in the right place? Right? Is the science that that that line is based on? Is that science outdated? Or could we could we take a different approach to try to give chefs more flexibility in terms of what they do and, and then also realize, I mean, there's already flexibility, right, you can already go and eat sushi, you can already go and eat, you know, there's jokes, there's jokes, going back years and years about sunny side up eggs in New Jersey, right? You know, because we and you can you can have them you can you can, you can have sunny side up eggs, even though there is a risk from that. And so I'm, I'm more about, like, let's talk about the risk. Let's Let's inform people about the risks. And again, I know chefs don't like to have things on the menu that says, If you order your if you order the sushi, you might get food poisoning. I know that's that's probably not good marketing. But from a education perspective, maybe that's the right. That's the right solution. Okay, yeah, I'm, what I would like us to all be able to play nicely and have discussions about these things in a logical way to get it gives people choice, consumer choice, give Chef's Choice, and still tries to protect public health as well.

I mean, the sushi thing is interesting, because we all know that there's no way that a sushi restaurant in the real life can pass health code because they don't wear gloves. And I don't want them to wear gloves. I know what I mean. And, and they don't wear gloves. And so, you know, they have the those things sitting out, they wiped down with a towel. I mean, there's not one thing that they do. Now, they have rice that's hardcore in the danger zone that that that health department has no way of testing the acidity of right? You know, it clearly doesn't grow. By the way. Do you also call it is it? Is it be serious? Because I always just call it like, be serious, be serious, like, what does it actually

make that same joke? Yeah, the full name of the organism is bacillus serial,

right? And that's what's going to happen if you leave rice out that hasn't been vinegared or sugared. Right. You have a decent chance of probably not dying, although kids have died, right? From be serious growing in that thing. Right, right.

Yeah, that's exactly right. Again, not every bit of rice is contaminated. But I liked the way you phrase it, you have a reasonable probability, we know that if you cook rice, and then you leave it at room temperature, or you cool it too slowly, actually, I was just hearing about an outbreak where they cooled the rice too slowly. And actually somebody an elderly person could die. So yeah, this was serious, is generally not the kind of disease that kills you. But guess what, if you're in a weakened state it for sure can, can kill you. And that's why that's why we don't want to leave rice at room temperature for long periods of time.

Except for let's look at the sushi restaurant where that's their whole job. That's the whole business model. And so it's like, these, these folks aren't using gloves. They're wiping things down with wet towels constantly, then, like which, and you know, that's not Sani solution. And then there, they have room temperature rice sitting out for the whole service. So it's like, you know, and I know that there are things in place to make that safe, but it's not in the code. And there's no way that because there's it's not just the difference between you, the scientist and the chef to the user. There's the code enforcement people as well. There's the there's you then there's the code writer, then there's the code enforcer who has to have the knowledge, then the person who cooks then the consumer, it's like crazy, right?

Yeah, yeah, yeah, you're actually right. The person that writes the code is not the same person that enforces the code. But with sushi rice, at that rice should as you mentioned, it should be a certified and that acidification process will allow you to keep that keep it at room temperature and should prevent the growth of Bacillus cereus. If it's been properly acidified.

Right, but then, you know, has there been cases where people have tried to go more modern and cut down the acid to an extent where it's actually become unsafe?

That's a good question. I don't know if that's the case. I know that we do. We do continue to have foodborne disease outbreaks from rice but it is more the situation where it's a it's a typically a Chinese restaurant or or an ancient restaurant and they prepare a big batch of rice and they just they just, you know, either cool it improperly or leave it at room temperature for long periods of time to make fried rice out of it. And and the the nature of bacillus food poisoning there's one kind of bacillus food poisoning that comes from a toxin. And once that toxin is in the rice, no amount of frying or cooking will get rid of that molecule, that toxin molecule, which is what causes the vomiting symptoms and so, but I don't I don't know of any cases of improperly acidified sushi rice causing illness, not that it doesn't happen. I just can't think of any examples of you know that that have come across my radar.

So you know, there's never going to poison anyone Jiro he puts way too much freakin vinegar in his voice. I'm sorry, those things are like, crazy. But like so you're saying it's probably doesn't take that much vinegar to actually do the trick plus their sugar as well. So it's like, it just doesn't take that much of a shift towards acid or towards a reduction of the water activity to have it not grow?

Well, I'm not sure it's reduction of water activity. Although it's interesting that you mentioned sugar, I think it's more it's more of a pH that's that's that's doing it right. And it's the acidity and the pH but But exactly how much you have to add. And where that cut point is where you're just a thing, like you have a certain amount of acidity that will stop the Sillas from growing, but then with a little bit less acidity, you might slow the growth. And so yeah, I haven't I haven't really dug into like the risk analysis of that to kind of figure out like, where exactly how risky it is and where you can where you maybe you can you can edge a little closer to risk but still be quote unquote safe.

Yeah, well, remember, it's not is it safe? Is it? Is it risky, different questions, different questions. Life is risky, you know, me biking here today, I almost got killed. So there you go. There we go. Yeah. And I mean, okay, so you bring us to an interesting point, when you say that, you know that there's this place where the be serious. And I can't call it anything but that where it's not that you are killing it. But it ain't growing. And I think the vast majority, a lot of the people who listen to this show, do kind of Suvi low temperature work. And I think this is where this is where the safety rubber meets the food poisoning road. Right? It set. There's all of this work that we do where it's true. We're not necessarily causing something that started out life unsafe to be safe all of a sudden, but we are also not making it worse. Right. And I think that's where the majority of our low temperature work is actually taking place. I mean, the majority of us aren't actually pasteurizing the food that we're cooking, what do you think?

Well, but I think we need to draw a distinction between the pathogen of choice or the pathogen that's likely to be in rice versus in in meat, right, Bacillus, or Clostridium botulinum, we want to control the growth because when they grow, they may toxin that and the levels of growth, at least with respect to bacillus, the levels of growth of multiplication of bacteria that you need to see before you get sufficient toxin formation to cause illness. That's different than salmonella, which is an infectious organism and which doesn't. It doesn't have to grow to cause illness. Now, granted, I'd rather eat a single salmonella cell than a million salmonella cells, but realize that even the ingestion of a single salmonella cell has a probability of illness, right? So if I could, if you believe the math and the science, if I could get 300 people to volunteer today to eat one salmonella cell, chances are in 24 to 48 hours, one of those people just due to the billiard ball, Luck of the salmonella cascading through their intestine, one of those people is going to be unlucky enough to be infected, and maybe even develop symptoms and become sick. And so the way that we're managing risk with rice is different than the way that we're managing risks with with let's say, Suvi cook. But again, there's a lot more subtlety we can get into with with cooking, because it's really about time and temperature. And it's about assumptions about, you know, the dose needed and then the starting concentration that you might have a need to begin with and all of

that right well, maybe that's kind of though, I think where a lot of our people kind of want to go mentally, right is to that level. And so then we're talking about okay, I mean, botch the botulism is the one everyone worries about right but I mean, Listeria I'm worried about a lot especially if you're going to chill it afterwards and store it right. Said a real good friend or family almost die from listeria. So it's what do we do about people when we're cooking in zone where because it happens all the time listing on fish, right, especially fish like red meats, I can cook a red meat, most red meats, I can Cook above 5455 Celsius, Celsius in that range. I am killing stuff I'm actively killing now, am I going to cook it long enough to get enough, you know, reductions of levels that we could talk about, but I'm actively killing stuff, right? When I'm doing fish, right? I'm lower, often lower, I'm often in the low 50s, like 5052 53. It's not and you're not cooking for a long time. So you're clearly not killing all of the pathogens of interest. And some pathogens of interest, right? Don't even really necessarily on paper anyway, start dying until you hit 55. Right. I mean, it mean, I just think people like you see all these numbers, and they get weirded out. So what about these zones where I'm cooking a salmon? Let's be specific, I'm cooking a salmon. I'm going to cook it to 52 Celsius, right? Let's say it let's say the salmon isn't a tube shaped and for the Senator to come up to that it takes an hour or 45 minutes, I now chill it and eat it. What am I doing to myself? What is actually happening? Right? Because once it gets up into 50, you know, 52 is? Am I in stasis? Am I growing? Is it the same as if I just eaten it right out of the fridge? Worse? Better? Where are we?

Yeah, so you there's a lot to unpack here. And also, there's actually a need to kind of get the numbers up in front of me and work through work through some stuff, because I don't want to mislead people. But I do want to come back to something that you said. You mentioned listeria, and I would put although Listeria is an infectious organism, it is not I don't put it in the same bucket as salmonella and pathogenic E. Coli. We know from dose response studies with listeria, although it is an infectious organism, it tends to be a high dose organism. And so as I mentioned before, the probability of illness from a single salmonella cell is on the order of one in 100, or one and 200, or one in 300. The probability of illness from a single listeria So even for somebody who's immunocompromised is much more in the ballpark of one in a million or even lower risk. And so generally speaking, the foods where listeria pose a risk are foods where because of that extended refrigerated storage, you mentioned that any surviving organisms have managed to grow to high levels, such that there's a reasonable probability of illness, that the cooking temperatures, with with subida is an interesting one. Because at some point, you're not cooking it, you're just simply incubating it right. And so I'm good. And we're sort of moving back and forth between degrees C and degrees after the the sort of the optimal growth temperature for many of these pathogens, including salmonella is right around body temperature, right. So they grow best at about 37 degrees C which is about 98.6 degrees F and as you move above that they grow more slowly, but then at some point, it switches over from slower and slower growth to starting to get some thermal inactivation. And yeah, and fish fruit like you said fishes for sure a challenge because it's really easy to to overcook it 120. And I haven't really sat here and done the math carefully. 125 degrees Fahrenheit or 52 degrees C. That seems like an awfully low temperature. And again, I know we had some correspondence before the before the this call about that I need to get those numbers up in front of me and sort of figure out what we know about where it is salmonella, because it's one thing to say okay, salmonella is not growing. And certainly if you're if you're quote unquote cooking it in the temperature where you're actually growing salmonella, that's not a best practice, but figuring out where that dividing line is between where growth stops and inactivation again, that's that's that's that's the sweet spot. Right? And that's where we want to be we want to be above that that

temperature right? Well in the early 2000s A lot of chefs were you know, fabricating their fish under kind of sushi grade conditions right so the concept was you can eat this raw, they would vacuum pack it and then they would store it as though they were storing stuff that would be sort of raw sushi style right? Then they would put it and they would cook it to the in Celsius ready for this. They will cook it in the 40s Right? Like like 50 was high they will cook it in the 40s but they would only do it for like 20 minutes. Basically warming it and you would get this kind of jewel toned kind of fudgy and nine out of 10 Well about half the people hate it and about half the people love it which is why you don't see it that often in restaurants anymore just because so many people are actually turned off by it right? But the people who loved it, loved it and it definitely looks amazing. Sometimes it can get really fishy which is the problem with it. But my argument for why that was okay was because it just wasn't it wasn't being cooked long enough to have anything bad happen right? So Bruno Cousteau the you know grandpa of Zeus Catalans he calls it you know, precise temperature cooking. You know, he was like, but it can grow it can cause histamines, I was like, okay, okay, we're gonna whatever man but you know, most things I didn't feel like people were making it too unsafe. It's when you it's when you're gonna cook something for an extended period of time and then chill it and then serve it later that I start getting worried No.

Well, yeah, so certainly if you are we'll have to use air quotes you if you're cooking something at 40 degrees C which is 104 degrees Fahrenheit, you're not really cooking it you really are incubating and and that is definitely within the temperature range where or salmonella can grow. Now, if you're quote unquote, cooking it for an hour or two, you're not going to get much salmonella growth in that hour or two. If you're going to cook it if you're going to incubate it to either cook it for for 10 or 12 hours or overnight. Well, now you're really just making an incubator there and then and then if you refrigerate it properly, well then now you're not getting any salmonella growth. But if you had some listeria, you're not going to kill the listeria at 40 degrees C and then if you do extended refrigerated storage, no will now Listeria is going to start to multiply. And then you could be amplifying the risk there.

No one I think was no one ever argued like those ones when they came back. You couldn't doggy bag that stuff. It had to be eaten or pitched. You know what I mean? Like no one was like anyone who doggy bag that let people take it home that you know that's like poison in a cup right there. That's no good. But why don't dogs get sick from this stuff?

What the organisms, there's like some, here's the thing some organisms make dogs. Don't make us sick, some that make us sick, don't make dog sick. And some some don't make either of a second, some will make both of us sick. So you really can't be you really you really can't. It's not it's not definitive.

But so let's say I'm cooking in the 50s. Now like I'm not I'm I'm up at like 5052. Right? What I'm interested in is the shape of the bacterial growth curve, right? Where it starts up in this exponential thing where it gets real fast, as you say, up towards you know, it's it's real low at the fridge level, and then it ramps way the heck up towards body temperature. It peaks out somewhere, right? And then after that peak, it kind of crashes precipitously, right. So it's like there are these zones that aren't in the kill zone. But they're pretty much in the same zone as refrigeration in terms of growth. Right.

Right. And you're absolutely right, that they drop off precipitously. And that's also part of the reason why our knowledge in this area is a bit fuzzy. It's it's challenging to do those experiments, right, it's relatively easy to study from room temperature down to refrigeration, because the change in the growth kinetics of the organism is more gradual above the optimum up to the maximum, like you said, it's a precipitous drop. So again, I'm just looking at the limits to growth when other conditions are near the optimum for salmonella. And the maximum temperature reported here is 46.2. So so that's a so you're talking about 50. So if you're, if you're quote unquote, cooking at 50, which is 122 Fahrenheit, you're outside the range for salmonella growth. So salmonella, concentration is not going up. You're outside the range for listeria, so listeria concentration is not going up the extent to which it's going down that we have to I'd have to go look at some some different numbers. Now I will point out, we've talked about Bacillus cereus, before bacillus series, apparently, according to this first I'm looking at right now can grow up to 55. Now, again, do we have Bacillus cereus? In fish? Well, not. Not a lot. But you know what you might have seen the sources as for former and so those spores can be anywhere. And so could you have bacillus spores on fish? Yeah, absolutely. You could. Could you could you be encouraging their growth at 50 degrees? Yeah, you might be. It's probably not growing super fast. But but it could. But again, again, it's all it's about time and temperature.

Right, because I just don't think the majority of us are cooking long enough to pasteurize and I'm also not that worried about it. When I cook for my family. I mean, maybe in a restaurant situation, I would have to probably pasteurize it, because that's the way the rules are written. But anyway, I'm gonna get to some Patreon questions because I will get I will get my head torn off otherwise. John Denton wrote in I recently bought a freeze dryer, and I'm curious whether or not the freeze drying process kills harmful microorganisms are just renders and dormant. I guess that removing 100% of their water content would kill at least some but perhaps not all. Thanks for the show.

Yeah, great, great question. And we can answer freeze drying and freezing at the same at the same time, both freezing and freeze drying. We'll kill some of the bacteria, but it's not a reliable way to kill to kill bacteria. And so yeah, and then you take the water out and you might stress the cells a little bit more to actually win. And we want to store bacterial cultures for long periods of time we actually freeze dried them. And so it's an excellent way to preserve bacteria for a long time. So, so yes, you might get some kills, you might get, you know, 90% kill, but you still got you still potentially have more there and you might not even get 90% Kill. So for sure it's not a definitive step.

Let me ask you this question is not a kill step. But let's say I eat it in the freeze dried state and I don't rehydrate it. What's the risk? In other words, will they rehydrate and become on dormant inside my gut?

entirely possible? Yes. Because you know, they're basically and yeah, so they're basically going to be reading, rehydrating as they move through your body and so they're not, you're not pooping out freeze dried particles, right? So they're getting hydrated at some point and yes, there's a potential risk.

Speak for yourself. All right. Dustin. Dustin Meldrum wrote in what does your home dishwashing and or kitchen cleaning routine look like? I'm less concerned about things going into and coming out of the dishwasher unless I should be. But I suspect I'm over washing some items while creating potential risks elsewhere. If I'm being honest, I'm really after bare minimum standard operating procedure. But we've all witnessed friends and family clean in ways that have made us feel sad, mad or glad. What is the best practice?