Koren: Which foods are the most difficult to prepare for space?
Kloeris: Anything that creates a lot of crumbs. Crumbs are very difficult to deal with in microgravity because they’re just messy. When they get loose, they can make it into the air filtration system. You have to find a way to clean them up, and that usually involves a vacuum cleaner. Anything that requires refrigeration to remain microbiologically stable is going to be impossible to send up there. We occasionally get to send ice cream because they’ll have a freezer for medical samples that’s empty on the uphill trip. When that happens, we can send some frozen ice-cream treats and they have to eat those pretty much as soon as the vehicle docks, because they’re going to have to fill up that freezer with medical samples.
Koren: Have you tried to develop a microgravity-friendly recipe that just didn’t work?
Kloeris: We’ve had it happen more than once. We tried a thermo-stabilized cheesecake and we were never, never happy with the results. So we gave up on that.
Koren: How about carbonated drinks like soda? Can astronauts drink that?
Kloeris: Not unless they’re packaged under pressure, like in a whipped-cream can. In microgravity, the carbonation will not remain with the beverage. It will separate. Coke and Pepsi flew in pressure vessels back in the ’80s on one flight, and at that time, they didn’t have a way to chill it. So it was like, okay, we had hot Coke and hot Pepsi, so what? You’re probably not going to want a lot of carbonation in your diet when you’re in microgravity anyway, because when you burp down here, it’s dry burp. When you burp in microgravity, it’s probably not going to be a dry burp.
Koren: What ... what kind of burp would it be?
Kloeris: Wet. You’re gonna have food coming with it. When you burp, you’re burping through that sphincter at the top of your stomach. That is not a full closure. So in microgravity, when you eat, the food floats high in your stomach. Burping in microgravity is probably not something you want to do a lot of.
Koren: Have you been thinking about what kind of meals NASA would need to prepare for longer missions, like a trip to Mars or into deep space?
Kloeris: The research team in our lab is trying to figure that out right now. For Mars, the food that they eat on the return trip will be somewhere between five and seven years old, so that is a huge challenge. We can actually make food that is microbiologically safe to eat for that period of time. But there’s very few foods in our current food system that would maintain sufficient quality after that long. Even though we can stop microbial changes in these products by preserving them, we can’t stop the chemical changes. The color, texture, and flavor are going to change, and the nutritional content is going to degrade. We’re looking into which items are most susceptible to degradation. A particular nutrient will be more stable in one food than in another. For instance, vitamin C is not very stable in thermo-stabilized products, but it’s very stable in powdered beverages.