Market: Per Capita Consumption of Eggs in Germany (2006-2023)
Per capita consumption of eggs in Germany from 2006 to 2023, measured in units.
Market: Total Egg Production in Germany (2004-2023)
Total egg production in Germany from 2004 to 2023, measured in millions of units.
Farming Methods (EU Directive 1999/74/EC)
Cage Rearing:
Conventional cage rearing has been banned in the EU since 2012.
Small group housing or "enriched cages" are permitted with minimum requirements for space, perches, nests, and litter.
Floor Rearing:
Hens are kept in an enclosed barn with free movement.
Maximum of 9 hens per square meter.
Free-Range:
Hens have access to an outdoor area.
Same housing conditions as barn rearing.
Minimum of 4 m^2 of outdoor run per hen during the day.
Organic Farming:
Outdoor requirements.
Maximum of 6 hens per square meter in the barn.
Organically grown feed.
More outdoor space for animals.
Space and Equipment Requirements
EU regulations stipulate at least 750 cm^2 of cage space per laying hen in small group housing.
In barn systems, 9 hens per square meter of barn space are permitted.
In free-range and organic farming, the runs for the hens must offer open access and at least 4 m^2 per hen.
Animal Welfare Law
In Germany, the Animal Welfare Act (TierSchG) regulates the species-appropriate keeping of laying hens.
Keepers must ensure that animals are not subjected to unnecessary suffering, pain, or harm.
The ban on killing male chicks (from 2022 in Germany) is an important innovation for animal protection.
Feeding and Water
Animals must have access to fresh water and balanced feed at all times.
In organic farming, at least 95% of the feed must come from organic farming, and the use of synthetic additives is highly restricted.
Hygiene and Health Management
Regulation (EC) No 852/2004 on the hygiene of foodstuffs requires regular health checks, cleanliness in stables, and the prevention of disease transmission.
Vaccinations and veterinary treatments must be documented.
Mandatory Labeling of Eggs
In the EU, there is a clear egg labeling requirement according to Regulation (EC) No. 589/2008:
0 = organic farming
1 = free-range
2 = barn rearing
3 = caged
This label must be printed directly on the egg, allowing consumers to recognize the type of farming.
Lighting
Hens need a certain amount of light hours per day to optimize their laying performance.
Regulations control the duration and intensity of light to simulate a natural day-night rhythm and avoid stress.
Air Condition and Ventilation
Strict requirements apply to barn ventilation and indoor climate to ensure that animals have sufficient fresh air and a comfortable temperature.
This promotes well-being and prevents respiratory diseases.
These regulations aim to ensure that the animals are kept in a species-appropriate manner and, at the same time, guarantee the hygiene, quality, and safety of the products produced.
3 Types of Breeds
Light laying breeds
White Leghorn
High laying performance
Very little meat approach – unfit for fattening
Laying breeds – white or brown hybrids
Medium weight breeds
Dual purpose breed (Rhodeländer New Hampshire)
Crossing of light and heavy breeds
Good laying performance combined with comparative high body weight
Laying breeds – white or brown hybrids
Heavy breeds
Fast growth
Sexual maturity occurs late
Less to no eggs
Laying breeds – white or brown hybrids
Life Cycle of a Laying Hen
Lifespan:
Commercial layers: 2 to 3 years of egg production; decrease of production, size, and shell quality over time.
Backyard flocks: 6 to 8 years (eggs for 3 to 4 years).
Laying:
Depending on day length – 14 to 16 hours of light.
Adequate nutrition, housing, and management.
Depending on breed, hens start to produce eggs at 18 to 22 weeks of life.
Winter:
Ovulation stimulated by daylight.
Egg production continues due to artificial light – supplemented to provide the required time of light.
Rate:
Ovulation occurs every 24 to 26 hours.
Regardless of fertilization (no rooster needed).
Ovulation of new yolk when the previous egg was laid.
26 hours to fully form an egg – maybe a day will be skipped.
Meat production from laying hens:
Genetics for egg production.
Tough meat – not comparable to typical meat-type chicken.
Stewing laying hen meat makes it more edible – used in soups.
A fair amount of fat that may need to be skimmed from the dish being prepared.
Special Needs
Proteins and amino acids:
Especially for the development of egg white.
Methionine and lysine (essential amino acids).
Total energy:
Has to match with the laying cycle.
Cereals (high in carbohydrates).
Calcium and phosphorus:
Eggshell.
Calcium to phosphorus ratio.
Quality of eggshell and bone health.
Vitamins and minerals:
Vitamin D accumulation of calcium.
Vitamin A & E immune response.
Fat and omega-3-fatty acids:
Enhanced content in eggs.
Fibers:
Enhanced digestion.
Physiology of Egg Formation
Ovary ripening of ovum
When yolk is released – migration to fallopian tube
Infundibulum
Magnum
Isthmus
Uterus
Finally, the completed egg is laid through the cloaca process needs 24 to 26 hours per egg.
Physiology of Egg Formation: Timeline
Maturation of egg in the ovary: Oocyte, Ovulation, Fertilization, Zygote
Infundibulum: 1.5 h
Magnum: 5.5 h
Isthmus: 8.5 h
Uterus: 15.5 h
Vagina: 20.5 h
Oviposition: 25 h
Physiology of Egg Formation: Longitudinal View of Egg
The main parts of an egg are:
Shell
Outer shell membrane
Inner shell membrane
Air cell
Thick & thin egg white
Vitelline membrane
Yolk
Chalaza
Egg Yolk
~70% water
~1/3 of DM proteins
~2/3 of DM lipids
Mixture of particles
Granula – tightly packed segment
Plasma – transparent, yellowish solvent
Lipids
Up to 35% of fresh matter
Almost completely bound to protein lipoproteins
Main fraction – granula with 27 % lipoproteins and plasma with 86 % lipoproteins
Amount of cholesterol in lipoproteins from 4 to 6 %
Egg Yolk Cholesterol
Synthesis in the liver production out of Acetyl-CoA – intermediate of lipid metabolism
Formation due to stabilize cell membranes and to synthesize hormones
Transport once synthesized, it is packed to lipoproteins (VLDL – very low-density lipoproteins) and released into the blood circulation of the hen
Lipoproteins as transporters for cholesterol to the developing ovum in the ovary
Storage in yolk essential role in development of cell membrane, precursor of steroid hormones
Necessary for growth and development of the embryo
Cholesterol in egg – naturally process in liver of hen
Function to support the embryo with nourishing and essential compounds
Egg Yolk: Essential for Nutrition and Structure
Proteins:
Lipovitelline occurs in combination with lipids and source of essential fatty acids and energy for the embryo
Phosvitine rich in phosphorus, binds iron and calcium – minerals for the growing embryo
Livetine source of nutrients and immunological function
Vitellogenin derivates
Albumins stability of structure
Vitamins
Primarily fat-soluble vitamins: A, D3, E, K
Some water-soluble vitamins: B-Vitamins and Ascorbic Acid
Partially bound to proteins
Only fat-soluble dyes: Xanthophyll (naturally), Carotenoids (synthetic)
Egg White
Fractions:
Outer fluid layer
Tough layer
Inner fluid layer
Chalaza
Inhibitory effect on microorganisms:
Lysozyme: Antibiotic – hydrolyzation of cell membrane
Ovotransferrin: Inhibition of growth – binding essential iron ions by chelation
Avidin: Inhibition of growth – complexing with biotin
Ovomucoid: Inhibitor of protease
Ovoflavoprotein: Antibiotic
Ovomacroglobulin
Ovostatin, complex formation
Cystatin: Inhibition of ficain (papain)
Eggshell
Mechanical protection for the embryo
Exchange of gas, water, and temperature while brooding
Mineral supply for the embryo
Physiology of Egg Formation: Eggshell Structure
The main parts of the eggshell are:
Cuticle
Vertical crystal layer/Palisades
Pore
Mammillary Cone
External shell membrane
Internal shell membrane
Eggshell Formation
Takes place in the uterus of the laying tract
Formation of a basic structure
Deposition of organic matter
Mainly protein and collagen
Deposition of calcium oxide
Feed Ca^{2+} taken up with feed
Bones as reservoir Ca^{2+}-restriction – mobilization of Ca^{2+} from bones
Transport of calcium
Resorption in intestine
Calcium ions are transported via transporting mechanisms to the uterus
Regulation of calcium level in blood – hormones calcitonin and parathormone
Crystallization
Deposition in calcite crystals
Building of a hard mineral shell
Process starts at the mammillary layer and ends at the outer cuticula
Formation of layers
First layer: mammillary layer
Then: sponge or pillar layer
Outer layer: cuticula – sealing of the shell (protection)
Influence of hormones
Estrogen and progesterone: key role in control of egg development and shell formation
Prostaglandin as the main player for deposition of Ca^{2+}
Collecting and Packaging of Eggs
Collecting:
Manual or automated → depending on farm size
Three keys to no egg cracks:
Control Conveyor: Aligns eggs sideways to transfer eggs smoothly to the Gentle Bar.
Air-cushion Gentle Bar: Receives eggs softly with an "air-cushioned" effect.
Feather touch Bar: Reliably ejects the eggs on the Gentle Bar.
Sorting
Checking eggs clean and intact
Sorting by size:
S - < 53 g
M – 53 to 63 g
L – 63 to 73 g
XL - > 73 g
Cleaning
Not allowed in the EU – mandatory in the US No EU eggs in the US allowed and vice versa
Cleaning and disinfection of eggs affects natural cuticula Complete chill chain obligatory
Labeling
Code:
Type of farming:
Organic = 0
Free-range = 1
Floor rearing = 2
Cage rearing = 3
Country code:
2 letters
E.g., DE, AT, …
Company number
Storage and Transporting
After packaging, store cool (+5 to +8 °C) and dry
Delivered to supermarket, market, or wholesalers
Traceability:
Due to labeling on egg and information on the package
Genetics and Egg Color
Depending on breed:
White egg – white ear disk
Brown egg – red or brown ear disk
Blue egg – Araucana Cream Legbar – due to the pigment Oocyanin, present during the formation of eggshell
Green eggs – mixture of brown and blue pigmented eggs
Pigments
Protoporphyrin IX:
Responsible for brown eggshell.
Produced in the final stage of egg formation.
Only colors the surface of the eggshell.
Oocyanin:
Produced in the early stage of eggshell formation.
Colors eggs blue.
Colors the whole eggshell.
Functional Properties in Food: Emulsification
Lecithin in yolk – natural emulsifier
Hydrophilic and hydrophobic parts
Used in mayonnaise, dressing, dough, etc.
Lecithin
Chemical structure – amphiphilic character
Phospholipid – mainly Phosphatidylcholine
Hydrophilic head – phosphate group:
Directing to aqueous phase
Lipophilic tail – fatty acid:
Directing into oily phase
Stabilization of the interface of the two phases
Lowering surface tension and, therefore, prevention of coalescence
Functional Properties in Food: Applications of Egg Yolk Granules
Applications:
As emulsifying and foaming agents
As a source of folates
As a matrix to develop films
As an encapsulation agent
Functional Properties in Food: Binding
Due to the coagulation of egg white – rigidifying a mixture
Rich in proteins (especially albumins)
Proteins hold structure and ingredients together
While denaturation (heat or mechanical impact), functional groups of amino acids become free, and a new organization may occur
Used in meat products, gratin, dough, etc.
Functional Properties in Food: Foaming and Loosening
Egg white can be used to form a foam
Mechanical impact introduces air
While heating, the foam solidifies and leads to a loose structure
Used in Baiser, sponge mixture, etc.
Functional Properties in Food: Applications of Egg White
Applications:
Chocolate mousse
Marshmallows
Foam mat dried powder
Meringue
Pudding
Angel food cakes
Custard
Surimi
Encapsulation
Factors Affecting Egg White Properties
Factors affecting properties of egg white foam
pH
Sugar and salt
Interaction with other biopolymers
Factors affecting gelling properties of egg white proteins (EWPS)
pH
Salt
Heat
Hydrocolloid gums
High pressure
Factors affecting the emulsifying properties of EWPS
pH
Gums
Heat
Emulsifier type and concentration
Functional Properties in Food: Gelling
Gel network (heating)
Crosslinking of proteins building up a three-dimensional network
Coagulation process leads to a stable structure
After denaturation, reactive side chains are present
Interactions:
Especially disulfide bonds (cysteine)
Hydrophobic interactions
Ionic bonds
Functional Properties in Food: Thickening
Due to the coagulation properties
While heating, proteins bind water and thicken a matrix
Creamy consistency - pudding
Functional Properties in Food
Coloring:
Especially yolk – attractive yellow color of baked goods or noodles
Moisture and freshness:
Binding of liquid – prevent drying
Leads to more freshness and enhanced texture over time
Used in cakes, baked goods, etc.
Aroma:
Mild taste, able to intensify other aroma components of food (fat in yolk binds aromatic components)
Inhibition of crystallization:
Inhibition of crystallization of sugar – smooth consistency of frozen or cooked desserts
Gloss and building of crust:
Egg yolk on the surface of dough – builds a glossy crust
Uniform production legislation for organic products and farming.
Industrieemissionen (IED) – industrial emissions:
Reduction of pollutant emissions in livestock farming.
Regulations on animal welfare:
Depending on husbandry criteria.
Regulations about feeding:
What feed may be used in conventional and organic dairy farming?
Dairy Cattle Farming: Conventional vs. Organic
Conventional:
No regulations about stock size.
6 m^2 moving area per cow.
Width of feed alley at least 320 cm.
Width of walkway 250 cm.
Stall width of 125 cm prescribed for cows weighing over 650 kg.
Organic:
Pasturage obligatory.
100% organic feed, min. 70% from the own farm or out of the region.
60% coarse fodder.
Max. two dairy cows per hectare.
Dairy Cattle Farming: Milk Yield
~7,000 kg per year (6,860 L) 18.8 L per day.
In Austria, there are cattle with a yearly production over 10,000 L (rare). This contrasts with other countries in the EU and on other continents.
Depending on fitness, practice of farming, feeding, and race.
High-potent breeding – high cell number, inflammations on the utter, claw diseases, disorders in fertility.
Breeds for Milk Production
Holstein
Fleckvieh
Braunvieh
Pinzgauer
Grauvieh
Jersey
Dairy Cattle Feeding
Adaptation to lactation (start, middle, late).
Dry period (preparation to calving two weeks previously).
Energy requirement:
Careful start with the energy supply (start of lactation).
Slow increase in concentrated feed after calving.
Avoid energy deficit in the early lactation stage.
High-quality forage:
Contaminations may influence rumen flora.
Acid neutral detergent fiber (18%) and neutral detergent fiber (28%).
Basic staple feed:
Hay.
Silage (grass or corn).
Rape (post-extraction).
Barley and wheat.
Corn (kernels).
Problem: Fiber vs. Energy.
Protein supply:
Supply by coarse fodder (especially pasture).
Extraction meal.
Grain legumes.
Fiber content: Important for the functional rumen.
High quality is required.
Minerals and vitamins:
Supplementation, especially during the grazing season.
Feed uptake:
Maximization at the start of lactation.
Care about reduced capacity for fodder intake.
Feeding technology:
Portioning of concentrated feed.
Crushing instead of milling for better rumen fermentation.
Dry period:
Avoid fattening.
Targeted feeding to prepare for the next lactation period.
Dairy Cattle Feeding: Rumen
Four stomachs of Ruminants:
Rumen: Fermentation chamber
Reticulum: Filtering of small particles
Omasum: Withdrawing water
Abomasum: Actual stomach
Influence of Feed on Milk
Vitamins:
Many of the known vitamins are found in milk
Riboflavin (B2) and vitamin B12 – particularly rich source
Fat-soluble vitamins A, D, E and K
Depending on dietary intake of cattle and fat concentration of milk
Water-soluble vitamins
B-Vitamins
Folates (folic acid)
Vitamin C
Milking Process
Preparation:
Sanitation: Cleaning teats to avoid contamination and prevent infections
Pre-milking:
Pre-checking of milk, looking for changes in color or flocculation
Stimulation: Promote the release of oxytocin
Milking Process Detailed Steps
Foremilk stripping and pre-treating (Initial clean)
Attaching the cluster
Milking Process: System Components
Vacuum pump
Air pipeline
Pulsator
Teat cups
Short milk tubes
Milk claw
Long milk tube
Milk receiver
Milk pump
Bulk tank
Interceptor sanitary tap
Milking milk line
Tanker
Recorder connection point
Delivery milk line
Milking
Attaching the milking cluster:
Should only be attached if the milk flow has been stimulated by oxytocin.
Avoid blind milking – may stress the udder and prolong the milking process.
Monitoring of milk flow:
Ensure complete emptiness of udder without unnecessary stress.
Avoidance of excessive vacuum or inappropriate pulsation rates.
Maintenance of milking system:
Ensure that the vacuum level and pulsator timing are set optimally.
Recommendation of a rhythm of 60 double cycles per minute.
Milking Process: Vacuum and Rhythm
Milking phase: Vacuum
Rest phase: Air at atmospheric pressure
Milking Process: Milk Flow
Milk flow rate over time
Automatic cluster removal
Post-processing
Cleaning and disinfection of teats
Monitoring healthiness of udder
Quality Control
3 Types of hazards:
A) Indirect
Veterinary applications
Environmental (air, feed, soil & water)
B) Direct
Milk utensils
Teat treatment
Milk preservatives
Processing
Packaging
Quality Control:
Cooling chain
Sanitation of transporting vehicles
Sampling for quality control
Documentation
Storage and Transport
Cooling chain:
Chill to <6°C (exception: processing within 4 h).
Without interruption.
Quality control:
Notation of quantity in transport vehicle.
Fat analysis of every batch before mixing with milk from other farmers.
Sanitation:
Material of transport containers stainless steel.
Cleaning and disinfection prior to refill.
Labeling:
Best before (MHD).
Amount.
Fat content.
Other ingredients.
Milk type.
Curing.
Storage:
Dairy
Cooling chain
Sanitary standards
Quality control
Retail
Detection of temperature
Packaging and labeling
Periodic control
Processing in Dairy
Collection of milk from the farms
The milk is pumped into a tank from the machine
Milk purification using a separator (+55°C)
Milk separator
Mixing tank
Homogenization
Pasteurization: cooling (+2°C), Milk (2.5%), +76°C for 20 seconds
UHT: +137°C +20°C for 3-4 seconds
Various technological milk prepackaging machines
Aseptic filling.
Purified milk
Skimmed milk
Cream 40%
Other production purposes
Physiological Process of Lactation
Steps
To spinal cord
Hypothalamus
Posterior Hypothalamus- pituitary hypophyseal
Mammary gland:
To blood
Alveolus
Ducts
Gland cistern
Teat cistern
Teat canal
Myoepithelial cell stimulated by OXT
Secretory cell
Mammary duct
Milk production and ejection
Alveolus
OXT release
Suckling and odour
Vocalization
Visualization
Lactation
Continuous secretion and storage of milk in alveolar cells and ducts within the mammary gland.
Secretion is continuous (and usually at a constant) rate – gradual increase in internal udder pressure.
Milk ejection is a neuro-hormonal reflex initiated by various stimuli at milking time; they cause the alveoli and small milk ducts to contract, forcing milk towards the udder sinus.
Most of the milk can be removed by suckling or milking.
Physiological Process of Lactation: Cell Model
Microvillus
Junctional complex
Nascent fat globule
Mitochondrion
Endoplasmic reticulum
Golgi vesicle with casein micelles
Golgi apparatus
Cytosol
Lysosome
Nucleus
Outer cell membrane (plasmalemma)
Ribosomes
Basement membrane
Regulation of Milk Fat Synthesis
Acetate and β-hydroxybutyrate absorbed into blood vessel – diffusion through blood circulation into mammary epithelial cells.
Activated – de novo synthesis of fatty acids takes place.
Short- and medium-chain fatty acids can be synthesized de novo.
Catalyzation of acetyl coenzyme-A carboxylase and fatty acid synthase.
Long-chain fatty acids cannot be synthesized de novo.
Milk: Main Quality Characteristics
Protein and fat content:
Periodically tested. Crucial for nutritional composition.
Bacteria and cell counts:
Low level – good hygiene practice, healthy cows.
Inhibitors:
Make sure that there is no antibiotic or other medicines present.
Freezing point:
Ensure that no stretching with water has occurred.
Milk Components
Milk is an emulsion of fat in water.
It is also a colloidal suspension of proteins.
Other compounds, including lactose and minerals, are fully dissolved in the solution.
Milk contains hundreds of types of protein, of which casein is the main type. The milk proteins form micelles. These micelles scatter light, causing milk to appear white.
Composition:
Water: 87.5%
Fat: 3.9%
Proteins: 3.4%
Lactose & Minerals: 5.2%
Fats in milk:
Droplets of fat in milk have an average size of 3-4 micrometers.
They consist mainly of triglycerides, and also contain fat-soluble vitamins.
Triglyceride: R-Fatty acid molecules
Palmitic acid: 23.6-31.4%
Oleic acid: 14.9-22.0%
Stearic acid
Myristic acid: 9.1-11.9%
Milk Components: Lactose
Lactose is a sugar found in milk.
People who are lactose intolerant are unable to digest it.
Lactose can be fermented by microorganisms to form lactic acid, causing the milk to sour.
Lactose and digestion
Milk: Structure
Uniform liquid
Spherical droplets
Plasma containing casein micelles and fat globules