I am not sure about isotopic activity and relationship to food safety and in what terms. There are myriad of things that can go wrong with food safety.

Isotopic Analysis is used to confirm the authenticity of food (e.g. Origin). Fraud is detected. In terms of food safety the analysis may narrow also the origin if there is a Food Safety problem. However, it is very expensive and difficult to use it as a routine method. I may give further contacts if interested.

Sure, I will be interested. Also, I would like to point here: Fraud detection for authenticity comes under Food Defense and may or may not be food safety per se. I would be interested in seeing Isotopic analysis for food safety. Please provide further contacts.

Thank you!

The question from Mohan is not about authenticity of food, which is determined by accurately analysing stable isotope ratio's, but safety in connection to radio active isotopes like 14C, 40K, and so on. These isotopes have normally a natural origin.

Well, as you have seen, I am more thexpert in food safety issues and I have not used isotop analysis for that. But an expert is Jörg Lickfett [address deleted] work [phone number deleted] workcell [phone number deleted] email [email address deleted]

He will be able to give more insights.

Dear members,

dear Kees Olieman, Anand Mohan ·, Sylvia Pfaff ,

upon isotopic activity, internal (inside food) radiation is born. The radiation itself some researchers may view it as "damaging". the quantity of radiation is low. The issue here is somehow different. Upon transmutation of the atoms, we should encounter a chain of different phenomenons, more so as the time goes by.

Yes in did, the isotopes are natural but they do have an effect that even so it is of natural origin, it is potentially destructive as I imagine.

I'll like to know RG members opinion on the issue.

regards,

Adrian Toader-Williams

What about the food stored in the International Space Stations where the cosmic radiation is extremely high. What transformations is the food exposed to?

I think, with respect to the massive direct (cosmic) radiation, the effect of radiation-exposed food will be quite low.

Ad hoc proof:

The astronaut has a similar chemical composition as the food, so the same nuclides are formed by the cosmic radiation within the food and within the astronaut.

But

a) The mass of the astronaut is much higher than the mass of the food he or she somsumes during several weeks. Short lived nuclides in the food might decay before consumption while the same short lived nuclides generated in the astronaut will damage the tissue all the time.

b) The astronaut suffers additionally from direct ionization effects (e.g. DNA damage) that do not affect the quality of food.

My guess is, that not only the direct effect of cosmic radiation on the astronaut is very much higher than the effect of irradiatied food. Moreover, the effect of external exposition by activated spaceship components will be higher than the internal exposure by activated food.

Among one of the areas I work in, we have developed and routinely use methods to detect whether food has been exposed to ionising radiation. This is routinely done in some countries as a sterilisation technique, delaying spoilage and hence reducing food wastage. It is also sometimes used in hospitals to prepare food for patients with impaired imune systems. The safety concerns with irradiation of foods are mostly related to irradiation of food that has already started to spoil, killing any bacteria that would be identified in traditional microbial activity analyses while still potentially leaving toxins generated by microbial action in the food. There is some evidence that irradiation may result in the breakdown of vitamins and other nutrients. But, overall it is not considered a health risk if irradiation is conducted on fresh produce. Though, in developed nations there is a consumer acceptance issue.

Of particular relevance to the question posed here, the food taken into orbit by astronauts has been irradiation sterilised since the earliest days of space flight. Clearly the effects of irradiation by cosmic rays will be slightly different from the use of gamma or beta sources, but the general effects would be the same - somewhat akin to very slow cooking. Cross sections for isotope production are small, and the amount of induced activity in food in space would be very small.

One needs to know the type of radiation the astronaut and the food is exposed to. And also the amount of radiation. Much of the cosmic ray radiation one finds on surface of Earth is secondary radiation. Here the high energy cosmic rays produce a shower of muons, electrons, gamma rays. In space there are high energy protons (mostly) and they are far fewer in number. But high energy protons mostly go through producing relatively smaller amount of damage. There is radiation (wind) coming from Sun which mostly does not reach surface of Earth. But I think that would not be much of a problem as they are low energy and absorbed by spaceship. I suppose people must have measured radiation dosage received by astronauts when they spend months orbiting Earth. Those measurements would give a more precise answer. In any case, radiation reaching Earth does not produce much damage to living beings (after all life has existed on Earth foe ages). On the other hand, the small damage produced leads to evolution of species, by altering genes. But this happens over a very very long period.

Dear Adrian:

The food (both vegetables and meat) was being exposed to 40K and 14C (as its natural components) and cosmic rays rather long before we have come here to eat it. So we (mankind and its evolutionary predecessors) managed to survive.

As to the food stored in the International Space Stations (ISS) where the cosmic radiation is extremely high, I believe that if an ISS is constructed Rad-Hard by Shielding sufficient to defend asronauts themselves any radiation-induced hazards due to chemical changes in dead organic matter are hardly possible, or am I wrong? Besides, it is always possible to experiment on Earth with irradiation of food planned to be stored in the ISS and to see what happens (see Alan's answer). I believe. a more serious problem for future longterm interplanetary travels might be some toxicogenic mutations in vegetables cultivated onboard which are impossible to predict. However all this are diletеantish comments of a non-specialist in radiation biology or cosmic medicine. I believe some specialist has got ready answers to your questions.

Nature can be seen as beautiful and harmonious but it also inspires fear in man

who has had to fight it in order to survive. Now, nature is threatened by man who

has become detached from it. Technology has endowed humans with the power of

a major geological agency, which may act on a continental or even planetary scale

(e.g. acid rain, photochemical smog, radioactive contamination, stratospheric

ozone depletion, climate change).

At present the interaction between man and nature is determined by the fact that in addition to the two factors of change in the biosphere that have been operating for millions of years—the biogenetic and the abiogenetic—there has been added yet another factor which is acquiring decisive significance—the technogenetic. As a result, the previous dynamic balance between man and nature and between nature and society as a whole, has shown ominous signs of breaking down. The problem of the so-called replaceable resources of the biosphere has become particularly acute. It is getting more and more difficult to satisfy the needs of human beings and society even for such a substance, for example, as fresh water. The problem of eliminating industrial waste is also becoming increasingly complex. The threat of a global ecological crisis hangs over humanity like the sword of Damocles. His keen awareness of this fact has led man to pose the question of switching from the irresponsible destructive and polluting subjugation of nature to a reasonable harmonious interaction in the "technology-man-biosphere" system. Whereas nature once frightened us and made us tremble with her mysterious vastness and the uncontrollable energy of its elemental forces, it now frightens us with its limitations and a new-found fragility, the delicacy of its plastic mechanisms. We are faced quite uncompromisingly with the problem of how to stop, or at least moderate, the destructive effect of technology on nature. In socialist societies the problem is being solved on a planned basis, but under capitalism spontaneous forces still operate that despoil nature's riches.

Unforeseen paradoxes have arisen in the man-nature relationship. One of them is the paradox of saturation. For millions of years the results of man's influence on nature were relatively insignificant. The biosphere loyally served man as a source of the means of subsistence and a reservoir for the products of his life activity. The contradiction between these vital principles was eliminated by the fact that the relatively modest scale of human productive activity allowed nature to assimilate the waste from labour processes. But as time went on, the growing volume of waste and its increasingly harmful properties destroyed this balance. The human feedback into nature became increasingly disharmonised. Human activity at various times has involved a good deal of irrational behaviour. Labour, which started as a specifically human means of rational survival in the environ ment, now damages the biosphere on an increasing scale and on the boomerang principle—affecting man himself, his bodily and mental organisation. Under the influence of uncoordinated production processes affecting the biosphere, the chemical properties of water, air, the soil, flora and fauna have acquired a negative shift. Experts maintain that 60 per cent of the pollution in the atmosphere, and the most toxic, comes from motor transport, 20 per cent from power stations, and 20 per cent from other types of industry.

It is possible that the changes in the chemical properties of the biosphere can be somehow buffered or even halted, but the changes in the basic physical parameters of the environ ment are even more dangerous and they may turn out to be uncontrollable. We know that man can exist only in a certain range of temperature and at a certain level of radiation and electromagnetic and sound-wave intensity, that is to say, amid the physical influences that come to us from the atmosphere, from outer space and from the depths of the earth, to which we have adapted in the course of the whole history of the development of human life. From the beginning man has existed in the biosphere, a complex system whose components are the atmosphere, the hydrosphere, the phytosphere, the radiation sphere, the thermosphere, the phonosphere, and so on. All these spheres are and must remain in a natural state of balance. Any excessive upsetting of this balance must be to the detriment not only of normal existence but of any existence at all, even human vegetation. If humanity does not succeed in preventing damage to the biosphere, we run the risk of encountering the paradox of replacement, when the higher plants and animals may be ousted by the lower. As we know, many insects, bacteria, and lichens are, thanks to their relatively simple structure, extremely flexible in adapting to powerful chemical and even physical factors, such as radiation. Mutating under the influence of an unfavourable environment, they continue their modified existence. Man, on the other hand, "nature's crown", because of the exceptional complexity of his bodily and mental organisation and the miraculous subtlety and fragility of his genetic mechanism may, when faced with a relatively small change in the chemical and physical factors of the environment, either produce unviable progeny or even perish altogether.

The argument about the fear which we are facing , is true , not because that the nature has changed its harmony but because the mankind has caused great harm to the balance of the nature.

Modern technology is distinguished by an ever increasing abundance of produced and used synthetic goods. Hundreds of thousands of synthetic materials are being made. People increasingly cover their bodies from head to foot in nylon, capron and other synthetic, glittering fabrics that are obvious ly not good for them. Young people may hardly feel this and pay more attention to appearance than to health. But they become more aware of this harmful influence as they grow older. As time goes on the synthetic output of production turns into waste, and then substances that in their original form were not very toxic are transformed in the cycle of natural processes into aggressive agents. One gets the impression that human beings are working harder and harder to organise bits of synthetic reality by disorganising the systems evolved by nature. Emphasising man's hostility to nature—a hostility armed with the vast achievements of modern technology—both natural scientists and philosophers are today asking themselves the pessimistic question: Is it not the fatal mission of man to be for nature what cancer is for man himself? Perhaps man's destruction of the biosphere is inevitable?

I must say, that most of these ideas are quoted from references, but I am totally believe in.

I believe that you're asking two separate questions - first, will food be affected from the exposure to cosmic radiation and second what are the health issues associated with radioactive materials in food.

With respect to the first question, the effects from exposure to external radiation to food are quite low. There have been many studies performed on the effects of radio-sterilization on food (from external radiation). To make a long story short, effects were similar to that which occurred during normal food cooking. The extent isn't important here primarily because sterilization occurs at an exposure level on the order of thousands of rads - which is a lethal exposure level to humans. Therefore, while astronauts are exposed to higher radiation levels than us, they definitely aren't exposed to lethal levels.

As for radioactive materials in food, we constantly are ingesting such materials. A perfect example is radioactive K-40. About 0.017% (if I remember correctly) of potassium is radioactive potassium-40. With a few calculations, one would find that an average banana has about 900 decays per minute of K-40; I find that really interesting because we consider a lab contaminated if it has 500 decays per minute of beta-gamma isotopes over a 100 cm2 area. I could imaging that the high energy cosimic radiation could be energetic enough to cause a neutron or proton to be ejected from an atom in food (which could make that atom radioactive), but you wouldn't be able to notice a statistically valid difference in the quantity of radioactive material present before and after.

Intake of radionuclides such as via ingestion of radioactively contaminated food and inhalation of radioactive gas causes internal exposure. Astronauts receive about effective dose of 1 mSv/day at ISS (dose depending on solar activity) for whom internal exposure is of very little relevance (for more details, please see ICRP Publication 123 issued in 2013).

For health effects in astronauts, you may be interested in our discussion as to circulatory disease mortality.

https://www.researchgate.net/publication/306364780_No_evidence_for_an_increase_in_circulatory_disease_mortality_in_astronauts_following_space_radiation_exposures?ev=srch_pub

For ingestion of radioactively contaminated food, you may be interested in our discussion as to food safety regulations following the Fukushima nuclear accident.

https://www.researchgate.net/publication/51718211_Food_safety_regulations_What_we_learned_from_the_Fukushima_nuclear_accident?ev=srch_pub

https://www.researchgate.net/publication/230585762_Safety_regulations_of_food_and_water_implemented_in_the_first_year_following_the_Fukushima_nuclear_accident

Article No evidence for an increase in circulatory disease mortality...

Article Food safety regulations: What we learned from the Fukushima ...

Article Safety regulations of food and water implemented in the firs...

Astronauts are not classified as being occupationally exposed in the sense of the ICRP system of radiological protection, and levels of risk following ionizing radiation exposure considered in astronauts are therefore different from those in workers on Earth and aircrew.

For stochastic effects, Table 7 in US NASA Technical Standard NASA-STD-3001 (latest revision made on 12 Feb 2015, about two years ago from now, freely downloadable from https://standards.nasa.gov/standard/nasa/nasa-std-3001-vol-1 ) lists example carrier effective dose limits in the use of Sv for a risk of exposure-induced death (REID) of 3% for missions of 1 year duration or less. For comparison, occupational effective dose limits of 20 mSv/year (with no single year exceeding 50 mSv) or 50 mSv/year have been used at a detriment adjusted nominal risk coefficient of 5.7%/Sv.

For tissue reactions (formerly called nonstochastic or deterministic effects), Table 1 in NASA-STD-3001 lists short term dose limits (30 day limit and 1 year limit) or career dose limits in the unit of mGy-Eq or mGy for non-cancer effects to the lens of the eye, skin, blood forming organs, circulatory system, and central nervous system. To derive mGy-Eq, the relative biological effectiveness (RBE) value is used for high linear energy transfer (LET) radiation. Of these, take, dose limits, for the lens for example. For astronauts (NASA-STD-3001), 1000 mGy-Eq/30 days, 2000 mGy-Eq/year, 4000 mGy-Eq/career are recommended. For comparison, occupational equivalent dose limits of 150 mSv/year to the lens have currently been used worldwide (which will be reduced to 20 mSv/year or 50 mSv/year in a year or in the few years in various countries).