^{Eggcyclopedia}

What is an Egg?

- “hard shelled reproductive body of the chicken”

- the egg was designed to fully support a chick from the moment of fertilization to the time of hatching (a total of 21 days)

Food Source Biological Value (%)

Milk (human) 95

Egg 94

Milk (cow) 90

Liver 77

Beef 76

Potatoes 67

Corn 60

- eggs are a highly nutritious food

Egg Facts

- a hen lays 280 eggs per year and that number is increasing through cross-breeding programs. In her lifetime she can produce over 100 times her body weight in eggs

- an egg is 11% shell, 58% albumin (white) and 31% yolk

- an egg is 65.5 % water, 11.8% protein, 11.0% fat, and 11.7% ash.

Purchase Power of $1.00 in the Supermarket (1999)

Item Grams of Protein

Cheese 40

Milk 47

Hamburger 53

Porterhouse 16

Chicken Liver 127

Chicken 118 Which would you rather eat???

Flounder 24

Eggs 126

Egg Types

by Shell – White, Brown, Blue

by Housing – Regular (caged), Free Run and Free Range

by Feed – Vegetarian, Omega 3, Vitamin E, etc.

by Combination – Organic

- productivity is best from caged, white layers. Depending on which specialty egg is desired, egg costs increase due to feed costs, increased mortality, labour costs, breed inefficiencies, land cost, etc.

Notes:

1. The shell colour makes no difference to the nutritional content of the egg.

2. White eggs mostly come from White Leghorn crosses, brown eggs from Rhode Island Red crosses. “White eggs from white birds, brown eggs from brown birds” .Araucana birds, which give us the blue eggs, do not follow this pattern and are not blue themselves. They are mixed colours of brown black and white.

3. Free run birds are housed on the barn floor, but do not go outside. Free-range birds are provided with access to the outdoors during daylight hours.

4. Organic eggs come from hens that are fed certified organic feed and are kept as free range birds.

Egg Quality

Eggs are rated on both internal and external quality.
Internal quality is what concerns the HRI trade.
Eggs are rated as Grade A, B, C or Rejects by the GRADER using a bright light during CANDLING
Grade A eggs will not necessarily meet the most demanding needs of a customer.

Notes:

1. While shell defects are a good indicator of flock health, they mean little to the consumer. For the most part, so long as the shell is not broken, the consumer is not overly concerned with shell defects. Unfortunately, the shell defects are the easy ones to find.

2. Grade A eggs have clean shells, a firm albumin, the yolk sits high, and the air cell is small. Grade B eggs may have a slightly stained shell, larger air cell, and/or a thinner white. Grade C eggs are cracked but not leaking and go to further processing where they will be pasteurized and make into liquid egg products.

3. Eggs will still be at their assigned grade at the end of their shelf life, assuming proper storage.

Runny Eggs

- Most common problem in the industry

- Golden Valley sorts 150 suppliers into suitability lists (HRI, Retail, Breaker)

- Major causes in order of prevalence:

- improper storage

- old eggs (rotation)

- hot weather during lay

- flock health

Notes:

- refer to runny egg fact sheet

Other Fairly Common Defects

Double yolks
Blood spots
Meat spots
Shell defects

Notes:

- refer to Egg Fact Sheets

Grading Eggs

After eggs are laid on the farm, they are collected and stored in a cooler on the farm and await to be picked up by the egg grading facility.

Upon arrival to the egg grading facility the eggs move to “farm egg” storage cooler. They are stored in this cooler based on their characteristics such as: white, brown, free run, free range, Omega 3 enriched, etc.

From the cooler, the eggs will be moved to the egg grading machine. This machine will unstack the eggs, wash them through a series of scrubbing brushes, and then they reach the candling booth. The candling booth is the point at which the egg is examined by an inspector and has a grade assigned to it. This is facilitated by a bright light under the eggs which allows the inspector to look inside the egg and assess the grade that should be assigned. Canada A is the grade that people will see at the local grocery store. Canada B is normally used by bakeries and similar institutional facilities. Canada C is used for further processing, also known as the “breakers”.

Canada A – normal shape, freely moving yolk, clean smooth shell, small air cell present.

Canada B – rough shell, some staining may be present on shell, irregular shape, larger air cell

Canada C – cracked shell (but not leaking), no staining

Reject – eggs of any other nature, not used for human consumption.

After the candling booth, the egg travels over a scale which will assign the egg it’s size. In Canada, eggs are assigned their size by weight, according to the following chart:

Jumbo - 70 grams and above ) in times where certain sizes are short,

Extra Large - 64 grams and above ) eggs that are in a higher weight range

Large - 56 grams and above ) can be sold in a lower range, but not

Medium - 49 grams and above ) the other way around. (ie. a large can be

Small - 42 grams and above ) packed as a medium egg, but a medium

Pee Wee - less than 42 grams ) can’t be packed as a large)

Eggs are graded one flock at a time, and the farmer’s payment for the eggs is based on the grade and the size of the eggs. As a flock ages, the eggs on average go through the size ranges and reach their peak at about 25% Extra Large, 65% Large and 10% Medium when the flock reaches a year of age. The flock is kept for about a year, and then the barn is cleaned and sanitized and the next flock is brought in and the cycle repeats itself.

The bird’s diet is formulated to provide enough calcium for a strong shell, protein for thick egg whites, and well balanced lipids or fat to provide a nutritious yolk. However, the shell is similar to a balloon in that there is only so much calcium and the bigger the egg is, the thinner the shell becomes as the walls “stretch” to accommodate the contents. Therefore, the shell on a small egg will be more durable than that of a jumbo egg.

After grading and weighing, the eggs are sent to a packing head that will put the eggs into either cartons for the retail market, fibre trays for over wrapping with plastic and sale as “cello” or bulk pack eggs (2 ½ dozen per tray), or plastic trays for use in further processing.

Once the eggs are packed they are stored in a finished product cooler and shipped from there to the retailer or institutional user. The eggs will typically reach the store three days from the time they are laid and will be Grade A until the date stamped on the end of the carton.

More information is available at the Canadian Egg Marketing Agency at:

http://www.canadaegg.ca/

or http://www.canadaegg.ca/english/educat/making-grade.html

Blood Spots

Blood spots are also called meat spots. Occasionally found on an egg yolk. Contrary to popular opinion, these tiny spots do not indicate a fertilized egg. Rather, they are caused by the rupture of a blood vessel on the yolk surface during formation of the egg or by a similar accident in the wall of the oviduct. Less than 1% of all eggs produced have blood spots.

Mass candling methods reveal most eggs with blood spots and those eggs are removed but, even with electronic spotters, it is impossible to catch all of them. As an egg ages, the yolk takes up water from the albumen to dilute the blood spot so, in actuality, a blood spot indicates that the egg is fresh. Both chemically and nutritionally, these eggs are fit to eat. The spot can be removed with the tip of a knife, if you wish.

Blood spots are more commonly found in brown eggs. The reason is two-fold. Firstly, the genetics of brown birds predisposes them to lay more eggs with blood spots in them. Secondly, during the candling procedure, the brown shell of the egg appears to have a red tint to it, which makes the task of looking for a red spot behind it extremely difficult.

Double Yolk Eggs

Double yolk eggs are the chicken’s equivalent to having twins.
Young hens whose egg production cycles are not yet completely synchronized often produce double-yolk eggs.
Hens that are old enough to produce Extra Large eggs often produce them, too.
Genetics of the bird is a factor, also. Occasionally a hen will produce double‑yolk eggs throughout her egg‑laying career.
It is rare, but not unusual, for a young hen to produce an egg with no yolk at all.
Double yolk eggs are nutritionally the same as single yolk eggs and perform the same in cooking and baking.

Candling Review

Candling is the process that the Egg Grader uses that helps them look inside the egg to estimate it’s quality. A bright light is projected into the egg and the person candling will assess a grade value to the egg. Canada A grade is the standard grade for eggs bought in a retail store. Lower grades are used commercially in baking and processed egg operations. These lower grades typically have cosmetic defects and if there is ever any concern with an eggs safety, it is rejected and cannot be used for human consumption.

Double yolk eggs can be very hard to spot during the candling process and appear to be just a large yolk. Sometimes two yolks can be spotted and the eggs are pulled aside for customers that request these eggs.

Q. If double yolk eggs are as rare as twins, why did I get more than one in a container?

A. There are approximately two hundred egg producing barns in B.C. These eggs are graded barn by barn at the grading plant. Most double yolk eggs are produced by young birds, so therefore barns that contain young flocks have a large concentration of these eggs. Usually a young bird will lay a small egg, but if the egg is a double yolk, it tends to be either large or extra large size. This tends to be true in humans as well, where expectant mothers tend to become “larger” for multiple birth pregnancies. Knowing all this, if you look at the extra large and large eggs coming from a young flock, the chances of it being a double yolker are actually quite high. So chances are, the container with lots of double yolk eggs is from a young flock of birds. If you got a single double yolk egg, it probably came from a more mature flock.

Egg Nutritional Information

One large egg contains:

Energy cal / 300 kJ

Protein 6.2 g

Fat 4.7 g

Polyunsaturates 0.7 g

Monosaturates 2.1 g

Saturates 1.5 g

Cholesterol 190 mg

Carbohydrates 0.6 g

Percentage of recommended daily intake*

Vitamin A 9 %

Vitamin D 8 %

Vitamin E 5.5 %

Thiamin 3 %

Riboflavin 14 %

Niacin 5.5 %

Vitamin B6 2 %

Folacin 15 %

Vitamin B12 29 %

Pantothenic Acid 15 %

Calcium 2 %

Phosphorus 6 %

Magnesium 2 %

Iron 4 %

Zinc 5 %

Iodine 17 %

* Based on Recommended Daily Intakes for Canadians established by Health Canada.

Eggs are the essential helpers in the preparation of many foods. They thicken custards and sauces, leaven soufflés and cakes, bind meats and stabilize emulsions, such as mayonnaise.

Eggs are a natural source of goodness because they contain so many nutrients. Canada's Food Guide to Healthy Eating suggests one to two eggs as a serving from the Meat and Alternatives group.

Eggs are an excellent source of high quality protein. Protein is essential for growth and development. Eggs contain all nine essential amino acids making them a complete protein. In fact, the pattern of amino acids found in eggs is so perfect for our bodies to use that scientists use eggs as a standard to measure the protein quality of other foods. In addition to protein, eggs also contain a significant number of vitamins and minerals, yet one egg has only 75 calories.

Eggs also contain a small amount of fat, about 5 grams per egg. More than half (52%) of this fat is unsaturated and one third (31%) is saturated. Fat is a compact source of energy, it also helps the body absorb fat-soluble vitamins (A, D, E, K) and makes hormones and bile acids.

Cholesterol is another type of fat found in egg yolks. In the past some people were concerned about eating foods that contained cholesterol. Current research suggests that dietary cholesterol has a minimal impact on most people’s health, and that the most effective means of decreasing blood cholesterol levels is to reduce your intake of saturated fat. As a result, foods such as eggs, milk products, meat and shellfish, that contain cholesterol can be a regular part of a healthy diet.

Egg Structure

SHELL

· the first line of defence against the entry of bacteria

· can be brown or white; nutritional value of the egg is the same

· composed mainly of calcium carbonate

· approximately 8,000 to 10,000 tiny pores allow moisture and gases in (O₂) and out (CO₂)

SHELL MEMBRANES

· there are two membranes on the inside of the shell

· one membrane sticks to the shell and one surrounds the white (albumen)

· the second line of defence against bacteria

· composed of thin layers of protein fibres

GERMINAL DISC

· appears as a slight depression on the surface of the yolk

· the entry for the fertilization of the egg

WHITE (ALBUMEN)

· there are two layers: thin and thick albumen

· mostly made of water, high quality protein and some minerals

· represents 2/3 of the egg's weight (without shell)

· when a fresh egg is broken, the thick albumen stands up firmly around the yolk

CHALAZA

· a pair of spiral bands that anchor the yolk in the centre of the thick albumen

· the fresher the egg the more prominent the chalazas unnoticeable when the egg is cooked

YOLK MEMBRANE (VITELLINE MEMBRANE)

· surrounds and holds the yolk

· the fresher the egg the stronger the membrane

YOLK

· the egg's major source of vitamins and minerals, including protein and essential fatty acids

· represents 1/3 of the egg's weight (without shell)

· yolk colour ranges from light yellow to deep orange, depending on the hen's food

AIR CELL

· forms at the wide end of the egg as it cools after being laid

· the fresher the egg the smaller the air cell

Grade “A” versus Grade “B”

Grade A Grade B

Break Out Covers a small area Covers a wide area

Appearance

Albumen (white) White is reasonably Small amount of thick

Appearance thick, stands fairly high; white; chalaza small or

chalaza prominent. absent. Appears weak

and watery

Yolk Appearance Yolk is firm and stands Yolk is somewhat

fairly high flattened and enlarged

Shell Appearance Approximates usual shape; Abnormal shape; unbroken;

unbroken; generally clean,* stained areas permitted;

some slight ridges/rough spots pronounced ridges/thin spots

that do not affect the shell permitted.

strength are permitted.

Usage Ideal for any use, but are Good for scrambling,

especially desirable for baking, and as an

poaching, frying and cooking ingredient in other foods.

in shell. (Age for a week in

a cooler to make peeling

hard boiled eggs easier).

Runny Eggs

Runny eggs are the most common complaint to the egg industry. When an egg is referred to as runny, normally it means that the white spreads over a larger area that is expected. When these eggs are fried, the yolk will not stand up as high as a non-runny egg, sometimes to a point that it makes contact with the grill and breaks. Poaching these eggs is problematic as well as the white does not hold together and the final product is not satisfactory.

Causes of Runny Eggs:

May things can cause runny eggs, but the result is the same. The protein in the white gives the egg white its thickness. If there is insufficient or broken down protein, the white will be runny. The lower the amount, the runnier the egg. There are numerous things that cause this, such as:

1. Old Eggs

From the moment an egg is laid, it begins to slowly deteriorate. Part of the deterioration process includes the breakdown of proteins. Therefore, when an egg is laid, the white will be at it’s best and as time goes on, it will increase in runniness. This is not a food safety issue, providing the eggs are stored correctly, simply the egg will not function as well as it did on Day 1.

2. Improper Storage

Proper Storage of eggs is critical to maintain their freshness. If eggs are not stored correctly, the will age at an accelerated rate. One day at room temperature will cause an egg to age more than would a week under refrigeration. A common problem is that many institutions pull out a stack of eggs for busy periods, place them beside the grill, and return the unused eggs to the cooler. The eggs on the bottom of this stack have been mistreated and may not perform well when it comes time to use them.

3. Hot Weather

Chickens, like all animals, eat to maintain their bodies. During cooler weather, a good deal of feed is consumed simply to keep their body temperature at the proper temperature. When the temperature in the barn increases, less energy is need to maintain body temperature, and so their feed intake is reduced. You will notice that pets during hot spells will go off their feed as well as the simply do not need to eat as much. The problem with this is that the feed has been formulated to provide the right level of protein and calcium to the bird if they eat normally. When the eat less, they have less protein and calcium to go into the eggs and you get thin shells and runny eggs. Some people say the birds are drinking too much water, but, in fact, it is the reduced feed intake that is the problem.