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. Spørgsmål om værdi og sikkerheden af forskellige kategorier af fødevarer er særligt vanskelige at besvare, fordi folk har at modificere fødevarer, næsten lige siden civilisationens begyndelse. In fact, without certain types of food modification, the human species might never have survived on Earth. I virkeligheden, uden at visse typer af fødevarer ændring kan den menneskelige art aldrig have overlevet på Jorden.
By far the most common and oldest type of food modification used by humans is food preservation. Langt den mest almindelige og ældste type mad modifikation brugt af mennesker er mad konservering. Imagine, for instance, a community of early humans in northern Europe trying to survive a long, cold winter with no method for preserving food. Forestil dig for eksempel, at forsøge et fællesskab af tidlige mennesker i det nordlige Europa for at overleve en lang, kold vinter med ingen metode til konservering af mad. Or picture a group of hunters in tropical Africa who have just killed a huge animal that could provide them with meals for weeks. Eller billede en gruppe af jægere i tropisk Afrika, der lige har dræbt et stort dyr, der kunne give dem mad i ugevis. 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. I begge tilfælde står mænd og kvinder problemet med opbevaring af madvarer, der er blevet tilgængelig på én gang til brug på et senere tidspunkt, ofte langt senere.
Over the millennia, people have discovered a variety of methods for keeping food from "going bad"—in other words, decaying. I årtusinder har folk opdaget en række forskellige metoder til at holde mad fra "går dårligt", med andre ord, henfalder. Cooking, smoking, freezing, and drying were among the earliest food preservation techniques. Madlavning, rygning, frysning og tørring var blandt de tidligste levnedsmiddelkonservering teknikker. The use of a broad range of spices, the most important of which was salt, also proved effective as a way of preserving foods. Anvendelsen af en bred vifte af krydderier, hvoraf den vigtigste var salt, også vist sig effektive som et middel til konservering fødevarer.
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. Selvom tidlige mennesker udviklet en række metoder til opbevaring af madvarer, er det tvivlsomt, at de vidste noget om de mekanismer, som sådanne teknikker konserves, de vidste blot, at de arbejdede. 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. Dybere forståelse kom ikke før omkring 19. århundrede, hvor forskere, såsom den franske kemiker Louis Pasteur (1822-1895) og den tyske bakteriolog Robert Koch (1843-1910) opdagede rolle mikroorganismer i nedbrydning af organisk materiale og spredning af sygdommen. 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). Disse forskere var i stand til at vise, at visse miljøforhold begunstiget væksten af bakterier (varme og fugt), mens andre modløse deres overlevelse (kølige temperaturer og et tørt miljø).
This information helped explain the success of various food preservation techniques. Denne information hjælper med at forklare succes i forskellige fødevarer bevaringsteknikker. For example, drying preserves foods because it removes much of the moisture that bacteria need to grow. For eksempel bevarer tørring af levnedsmidler, fordi det fjerner en stor del af den fugt, at bakterier skal vokse. Freezing works because it lowers the temperature of food to the point that the growth of bacteria is severely inhibited. Frysning fungerer, fordi det sænker temperaturen af fødevaren til det punkt, at væksten af bakterier alvorligt inhiberet. 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. Krydderier er effektive til en række årsager, den ene er, at de kan frigøre kemiske forbindelser, der er toksiske for bakterier, nelliker, for eksempel frigiver en forbindelse, der kaldes eugenol, at forsinker væksten af bakterier. And smoking food preserves it because smoke, like spices, contains a number of chemicals that inhibit the growth of bacteria. Og rygning maden bevarer det, fordi røgen, ligesom krydderier, indeholder en række kemiske stoffer, der hæmmer væksten af bakterier. One of the most widely used of modern synthetic preservatives, butylated hy-droxyanisole (BHA), is a natural component of smoke. En af de mest udbredte af moderne syntetisk konserveringsmidler, butyleret hy-droxyanisole (BHA), er en naturlig komponent af røg.
Introduction Indledning 
The History Of Food Modification The History Of Food Ændring 
Food Additives Tilsætningsstoffer 
Synthetic Foods Syntetiske Foods Genetically Modified Foods Genetisk modificerede fødevarer Food-Borne Illnesses And Irradiation Of Foods Food-Borne Sygdomme og bestråle fødevarer Organic And Natural Foods Økologiske og Natural Foods 
