Questions about the value and safety of different categories of food are especially difficult to answer because people have been modifying foods almost since the dawn of civilization. Pitanja o vrijednosti i sigurnosti različitih kategorija hrane posebno su teško odgovoriti, jer ljudi su modificiranje hrane gotovo od zore civilizacije. In fact, without certain types of food modification, the human species might never have survived on Earth. U stvari, bez određene vrste hrane modifikacije, ljudska vrsta možda nikada ne bi preživio na Zemlji.
By far the most common and oldest type of food modification used by humans is food preservation. Daleko najčešći i najstariji tip hrane izmjeni koriste ljudi je konzerviranje hrane. Imagine, for instance, a community of early humans in northern Europe trying to survive a long, cold winter with no method for preserving food. Zamislite, na primjer, zajednice praljudi u sjevernoj Europi pokušajima da prežive dugu i hladnu zimu bez metode za čuvanje hrane. Or picture a group of hunters in tropical Africa who have just killed a huge animal that could provide them with meals for weeks. Ili slika grupa lovaca u tropskoj Africi, koji su upravo ubili veliku životinju koja bi im mogao pružiti obroka za nekoliko tjedana. In both cases, men and women faced the problem of preserving food that has become available at one time for use at a later time—often, much later. U oba slučaja, muškarci i žene suočavaju s problemom očuvanja hrane koja je postala dostupna u jednom trenutku za korištenje na kasnije vrijeme često, mnogo kasnije.
Over the millennia, people have discovered a variety of methods for keeping food from "going bad"—in other words, decaying. Tijekom tisućljeća, ljudi su otkrili razne metode za čuvanje hrane iz "ide loše", drugim riječima, propadaju. Cooking, smoking, freezing, and drying were among the earliest food preservation techniques. Kuhanje, pušenje, zamrzavanje, sušenje i bili su među najranije konzerviranje hrane tehnika. The use of a broad range of spices, the most important of which was salt, also proved effective as a way of preserving foods. Korištenje u širokom rasponu od začina, najvažnija od kojih je sol, također pokazao učinkovit kao način čuvanja hrane.
Although early humans developed a variety of methods for preserving food, it is doubtful that they knew anything about the mechanisms by which such techniques preserved foods; they simply knew that they worked. Iako su rani ljudi razvili različite metode za čuvanje hrane, upitno je da nije znao ništa o mehanizmima kojima se takve tehnike sačuvanih hranu, oni jednostavno znao da su radili. Deeper understanding did not come about until the 19th century, when researchers such as the French chemist Louis Pasteur (1822-95) and the German bacteriologist Robert Koch (1843-1910) discovered the role of microorganisms in the decay of organic material and the spread of disease. Dublje razumijevanje nije došlo sve do 19. stoljeća, kada su znanstvenici, kao što je francuski kemičar Louis Pasteur (1822-1895) i njemački bakteriolog Robert Koch (1843-1910) otkrio ulogu mikroorganizama u raspadanja organskog materijala i širenja bolesti. These scientists were able to show that certain environmental conditions favored the growth of bacteria (heat and moisture), while others discouraged their survival (cool temperatures and a dry environment). Ti znanstvenici su uspjeli dokazati da određeni uvjeti okoliša pogoduje rastu bakterija (toplina i vlaga), dok su drugi obeshrabreni njihov opstanak (hladne temperature i suhi okoliš).
This information helped explain the success of various food preservation techniques. Ova informacija je pomogao objasniti uspjeh različitim tehnikama konzerviranja hrane. For example, drying preserves foods because it removes much of the moisture that bacteria need to grow. Na primjer, sušenje čuva hranu jer uklanja više od vlage da bakterije moraju rasti. Freezing works because it lowers the temperature of food to the point that the growth of bacteria is severely inhibited. Zamrzavanje radi jer snižava temperaturu hrane do točke da je rast bakterija teško je inhibirano. Spices are effective for a variety of reasons, one being that they may release chemical compounds that are toxic to bacteria; cloves, for example, release a compound called eugenol that slows the growth of bacteria. Začini su na snazi za niz razloga, jedan se u tome da mogu objaviti kemijske spojeve koji su otrovni za bakterije, cloves, na primjer, objaviti spoj nazvan eugenol koji usporava rast bakterija. And smoking food preserves it because smoke, like spices, contains a number of chemicals that inhibit the growth of bacteria. I pušenje hrana čuva, jer dim, kao što su začini, sadrži niz kemikalija koje inhibirati rast bakterija. One of the most widely used of modern synthetic preservatives, butylated hy-droxyanisole (BHA), is a natural component of smoke. Jedan od najčešće korištena modernih sintetičkih konzervansa, butil HY-droxyanisole (BHA) je prirodni sastojak dima.
Introduction Uvođenje 
The History Of Food Modification Povijest hrane izmjeni 
Food Additives Prehrambeni aditivi 
Synthetic Foods Sintetička hrana Genetically Modified Foods Genetski modificirana hrana Food-Borne Illnesses And Irradiation Of Foods Hranom Bolesti i zračenje hrane Organic And Natural Foods Organske i prirodne hrane 
