Everything you need to know about the egg!

The famous question: which came first, the chicken or the egg? Not even the most brilliant scientists can answer these questions. However, you can find answers to other egg-related questions here.

  • The Labelling System


    Photo: Stockfotos-MG

    To provide the highest degree of transparency to the consumer, a comprehensive labelling system is used which gives detailed information on the origin of the eggs.

    From 1st January 2004, all eggs in Europe must be stamped with a uniform label.

    This label is made up of the following character strings.

    Example: 1-DE-1234501

    The first number tells you the form of rearing of the laying hen:

    0 – Organic
    1 – Free-range
    2 – Barn

    The next combination of letters indicates the country of production:

    AT - Austria
    BE - Belgium
    BG - Bulgaria
    DE - Germany
    DK - Denmark
    ES - Spain
    FR - France
    HR - Croatia
    IT - Italy
    NL - Netherlands
    PL - Poland
    RO - Romania
    SE - Sweden
    SI - Slovenia

    Then follows the laying farm number with the hen house number (last number).

    In Germany, the federal state can additionally be derived from the first two numbers of the egg farm number:

    01 - Schleswig-Holstein
    02 - Hamburg
    03 - Lower Saxony
    04 - Bremen
    05 - North Rhine-Westphalia
    06 - Hessen
    07 - Rhineland-Palatinate
    08 - Baden-Wuerttemberg
    09 - Bavaria
    10 - Saarland
    11 - Berlin
    12 - Brandenburg
    13 - Mecklenburg-Western Pomerania
    14 - Saxony
    15 - Saxony-Anhalt
    16 - Thuringia

    Please note that in Italy and France, letters are also used to denote the farm. For example: 1-IT-123AB456 or 1-FR-ABC01.

  • How an Egg Comes into Being


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    The egg—the nucleus of life—is a complete structure that is built up layer by layer from the inside to the outside. A "hard-working" hen only needs 24 hours to accomplish this!

    The sexual organs of the hen are initially set up in pairs; however, in poultry, only the left-hand ovary is active, while the right-hand one atrophies completely.

    In the left ovary, the egg follicles mature until they reach the size of a normal yolk. After ovulation, they arrive through the funnel into the upper part of the fallopian tube. If hens were kept in a brood, fertilization would take place here; however, to simply lay eggs the hen does not need a rooster.

    In the main part of the fallopian tube are glands which cover the yolk with egg white. First, the yolk is surrounded with a thick layer of egg white, then with a thinner layer. This process takes around three hours. Now the egg-in-the-making arrives in the narrow part of the fallopian tube (isthmus), where first of all the two shell membranes are built up. The air chamber builds up between the two membranes at the blunt end of the egg.

    The egg passes into the uterus and remains there for the next 20 hours, where calcium is excreted from glands which goes to form the shell. Here, the egg gets its specific colour and, shortly before laying, the outer coating (cuticle), which protects the egg from intrusion by contaminants. One hen lays around 300 eggs a year.

  • Information on Egg Quality


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    Cleanliness and hygiene determine the quality of eggs. In addition, eggs are examined for freshness. The use-by date, which is found on every box, is important.

    Farms must be able to demonstrate in-house hygiene management. This is supplemented by external checks on hen house residues and salmonella screening. Laying hens may only be supplied with hygienically clean drinking water. Regular quality analyses ensure this.

    For purposes of quality control, regular samples are checked at retailers of organic, free-range and barn reared produce.

  • Information on Nutritional Values of Eggs


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    Since the egg is a natural product, the nutrients vary depending on the season, feed and age of the hens.

    This nutritional overview can therefore be seen as an average, and refers to the nutrients in eggs with 100g, and 52g or 60g of edible component in an egg still in its shell. For an egg content of 52g, an egg with a weight of 58g is the basis, and the shell component is 6g. This equates to an egg of weight class M.

    Nutritional values 100 g 52 g 60 g
    Calorific value 153 kcal 83 kcal 97 kcal
      638 kJ 346 kJ 402 kJ
    Protein 13 g 7 g 8 g
    Carbohydrates 0,6 g 0,3 g 0,4 g
    - sugar <0,5 g <0,5 g <0,5 g
    Fat 11 g 6 g 7 g
    - saturated fatty acids 3,3 g 1,7 g 2,0 g
    Salt 0,32 g 0,17 g 0,19 g


    Incidentally, in cooked eggs the nutritional values remain unchanged as long as the shell is not cracked during cooking and egg white is not leaked.

  • The Yolk Colour of an Egg


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    There are many theories as to why eggs have different yolk colours. The answer is very simple: the yolk colour is determined by the feed consumed by the hen, and the natural colourings contained in the feed give the yolk its colour. Natural colourings called carotenoids occur in different concentrations in different kinds of fruit and vegetables. Yellow colourings are also contained in the corn and grass in hen feed, and give the yolk a strong yellow colour. The more a hen pecks up, the stronger is the colour.

    However, the use of carotenoids in hen feed supports above all vital functions in the organism. Many carotenoids are converted to vitamin A in the body. These help to protect the body cells and the skin, to detoxify, to strengthen the immune system and are important for sight.

  • How to Determine Egg Freshness


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    A fresh egg when broken open has a large ring of slightly cloudy, thick (gelatinous) egg white around the yolk. Very little runny egg white can be found near the edge. The longer the eggs are stored, and especially in warmer conditions, the more fluid even the gelatinous egg white becomes. The eggs literally "melt".

    You can see this in an intact egg from the position of the yolk: in a fresh egg, the gelatinous egg white surrounds the yolk like a coat and thus holds it in the centre of the egg. In liquefied egg white, the yolk rises up in the shell because it is specifically lighter. If "old" eggs like this are cooked, the yolk is likely to be found near the edge. In eggs, which are broken open, the yolk is flatter and more fragile, since the skin of the yolk loses stability with storage.

    Outside the hen house, eggs should be stored in a place which is free of dust and odour and at a temperature of below 20°C. The ideal temperature for egg storage should be between 15°C and 18°C. During longer periods of storage for eggs intended for processing, the temperature should however be lowered to 1°C to 5°C. After purchase, eggs should be immediately placed in a fridge so that they stay fresh longer.

  • Weekly Markets


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    Many consumers only buy eggs at a weekly market on principle, since they have particular confidence in this marketing channel. KAT, on the other hand, intentionally declines to offer a guarantee for these unpacked eggs, which are sold loose, since they cannot be a part of the closed KAT control system. As a matter of principle, KAT only controls eggs from barn, free-range and organic production. Every egg must have already been stamped at the laying farm with the producer's code in order to avoid possible mistakes at the packing stations.

    Only eggs originating on KAT laying farms, packed in KAT certified packing stations and sold by food retailers can display the KAT label on the egg box.

  • What Are Egg Products?


    Photo: thinkstock

    Hidden eggs can not only be found at Easter—you can find them all year round in unexpected places, in so-called egg products. As well as noodles, cakes and biscuits, these oval miracles are also used as binding agents for ice-creams and milkshakes, for creating foam in soufflés, and for manufacturing wine, cosmetic and medicinal products. It is all the more important with processed eggs to watch out for the origin of the eggs. The KAT-label "Egg origin – controlled by KAT" for broken eggs gives consumers the guarantee that the eggs come from alternative rearing. Only foods which have been manufactured without using any eggs from battery or small group rearing receive this logo. The guarantee that processed eggs come from alternative rearing systems is made in a similar way as for the purchase of loose eggs: a database-supported, quantitatively based monitoring system with safeguards on goods movements ensures that the eggs are part of a closed traceability system.

  • The Egg of Columbus


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    "The egg of Columbus" is a phrase which refers to a deceptively simple solution to a seemingly unsolvable problem.

    The story goes that Christopher Columbus, during a meal given by Cardinal Mendoza in 1493 after his return from America, is challenged that it must have been very easy to discover the "New World", after all anyone could have done this. Thereupon Columbus challenges those present to balance an egg on its end. Many attempts are made but no-one manages to do this. Finally, everyone is convinced that this is an impossible task and Columbus himself is asked to attempt it. He hits the end of his egg on the table so that it is slightly dented and the egg stands up.

    Originally, the anecdote of the egg of Columbus was attributed by the Italian artist Giorgio Vasari to his countryman Filippo Brunelleschi; this architect was supposed to have won the contract to build the dome of the cathedral of Santa Maria del Fiore by solving the "egg problem". This would certainly fit with the anecdote, since the cathedral dome in Florence is obviously reminiscent of the shape of an egg which has been dented at one end. In a work by the historian Girolamo Benzoni, however, the story is found transferred to Columbus. Anyway, Vasari admits to having learnt of the incident by hearsay.

    Some people believe the story originates in the Middle East.