Why is Raw Fish Safe, but not Raw Meat?

[00:00:00]Why is it completely fine to eat the raw fish, but you really should not eat raw meat and especially not raw ground meat as used in a hamburger, for example?

[00:00:09]Well, I love eating sushi, raw fish, sashimi, all of that stuff. Well, I enjoy it a lot. Well, if you've watched some of my early videos, you've already you already know that eating raw or undercooked ground beef uh can actually be quite dangerous. So, what's the difference to the fish? Well, the difference is actually due to two things. First of all, the way that the fish is processed and all of the microbiology involved. And the microbiology in meat and the microbiology of fish is actually quite different.

[00:00:37]Now, in this video, I want to to look at four things. First of all, why is raw fish safe to eat, but raw ground beef is not? Well, that's the main question of the video. Second, whether raw fish really is without danger or whether something is hiding in it. Of course, spoiler alert, there is something else hiding in raw fish. Third, I will explain why freezing of raw fish is actually important here. And it's not because of food preservation alone. And fourth, why is smoked fish not automatically safe? So, let me start with a meat. Now, when an animal is slaughtered, it's possible for bacteria from the digestive system of the cow to reach the surface of the meat during the slaughtering process. Now, when you eat a steak, the outside of the steak is fried, of course, and the heat kills the bacteria on the surface. And the inside uh stays raw or undercooked, and that's completely fine because the bacteria were only able to live on the outside and they were not able to reach the inside of the meat.

[00:01:36]Now, the problem begins when you grind the meat. Grinding takes those surface bacteria and mixes them all the way through. So, now the bacteria on are on the inside as well. And lightly cooked or undercooked patty, hamburger patty, may never get hot enough to the middle.

[00:01:53]Now, the problem begins when you grind the meat. Grinding takes all surface bacteria and mixes them all the way through, so now the bacteria are also inside as well. Um and a lightly cooked or a raw patty may never get hot enough um in the middle to kill them. Now, there are several documented cases where this has actually caused uh serious infections and even deaths. For example, there's a disease called HUS, hemolytic uremic syndrome, which uh can be caused by certain bacteria from undercooked ground beef. So, it's a real risk and not just a theoretical one. Now, I made a separate video about this uh if you're interested. Now, fish um however, has an entirely different risk pattern. The dangerous intestinal bacteria we just talked about are essentially absent in fish. Fish is of course not free of bacteria, no food actually is, uh but the specific bacteria that make raw ground beef dangerous, the ones that uh can cause the disease like HUS, are essentially not present in fish um as long as the fish uh live in clean water.

[00:02:51]That's really important. Um if the water is contaminated with uh sewage, then of course it's a different thing. Now, this one is actually the main reason why raw fish is bacteriologically safer than ground meat. The it's the absence of those dangerous bacteria. But, this does not mean that raw fish is completely without risk because there is a different problem, and that problem is hm you've guessed it parasites. There are certain parasites that can live inside the fish, and when a human eats them, then they can cause problems. And one uh common example is a nematode worm. It's a roundworm. It's called Anisakis. Now, if you eat it alive, then it can cause severe stomach pain because the worm tries to make a hole in the wall of your stomach. Not really fun.

[00:03:32]Now, how is this avoided? Well, right after the fish is caught um it's shock frozen. This often already happens immediately on the boat already. So, the freezing kills the parasite. Freezing does not reliably kill bacteria, but it does stop the bacteria from reproducing, and for the parasite, the cold is enough, the freezing is enough to actually destroy it. Now, maintaining the cold chain and keeping the fish frozen shortly before use is therefore also extremely important. So, I wanted to see this effect for myself, so I did a little experiment. I breed some tiny nematode worms myself. They're called vinegar eels and they're used as fish food for people who have a home aquarium. So, these worms are quite different and they're entirely different actually from Anisakis, of course, but they are still roundworms and you can see here that they still move around quite actively. Now, I put the slide with the worms into my freezer for, let's say, half an hour and when they thaw again, which is what happens, then they have stopped moving. So, the reason is that freezing causes the damage to the cells of these worms and the damage it kills the worms. And the same thing also happens, of course, with the parasites and that's why there are laws and rules about freezing fish after it's been caught. Now, the last thing I want to talk about is smoked fish, a smoked salmon, for example. Now, smoking does not automatically make fish safe. It depends on how the fish is smoked because there are really two methods, cold smoking and hot smoking. Cold smoking does not get hot enough to reliably kill bacteria and parasites, and hot smoking does, but at that point the fish, of course, is basically has been cooked. So, the real answer is not if the fish is safe and meat is dangerous, the real answer is that every risk has its own solution and must be managed differently. Different dangers need different treatments, of course. For bacteria on the surface of meat, then, of course, the treatment is heat and that you properly cook a burger patty, for example. And for the parasitic fish, in this specific case, the treatment is freezing. So, you see there is no single method that makes all food safe, but generally I do recommend if you cook the food, then a lot of bacteria and parasites are killed. Of course, if poisons and toxins have already accumulated on the fish due to bacteria reproducing, then that's of course again a different question. I know it's all very complicated. That's why I made a whole bunch of videos to explain all of this. Happy micro hunting as always and hope to see you in the next video. Bye-bye.