Eqq Quality and Processing

Question 1

what is the yolk

Answer 1

• blastoderm (fertile) or germinal dis (infertile)
• vitelline membrane (protein)

Question 2

what is the albumen

Answer 2

• produced in the magnum and shell gland
• chalaziferous or inner thick (narrow band over the entire yolk) forms the chalazae cords
• inner thin and outer thick (proteins)- texture due to presence of ovomucin fibres
• outer thin - derived from shell gland

Question 3

what is the structure of the egg

Answer 3

• shell membrane - two membranes ( joined at the top of the egg)
• shell - protection and gas exchange (12% of egg, mostly calcium carbonate) = mammilary abd spongy (pallisade layers)
• cuticle or bloom - just before the lay

Question 4

what do each of the shell membranes do for the egg

Answer 4

• one stays on the shell
• one detaches and creates the air pip

Question 5

what does the cutical do for the egg shell

Answer 5

• stops bacteria and dehydration

Question 6

what is a cutical

Answer 6

• protein secretion - the reason why the egg is wet
• water resistent ( preotects egg from susceptibility of egg to bacterial penetration immediately after oviposition
• partially closing pores
• anti bacterial proteins

Question 7

what influences egg size

Answer 7

• inheritance (breed = different weight)
• body weight (relationship)
• nutrition (protien or amino acid content, energy, dietary fat, linoleic acid = all yolk)
• environmental factors - lighting regime - longer days, egg will sit in oviduct longer = larger eggs
• environmental temperature - too hot = not eating
• birds age

Question 8

what influences egg shape

Answer 8

• important from a market standpoint (breaking during processing, consumer appeal, can be indicator of poorer interior quality)
• disease - infectious bronchitis ( heat sterilization= can cause eggs to be misshapened)
• multiple eggs in oviduct - double yolk

Question 9

how can you measure egg shell thickness or strength

Answer 9

• specific gravity = the more dense the shell, the more salt the water needs to make the egg float
• micrometer
  -% shell - weigh egg- crack egg and measure egg shell
• breaking strength = how much force it takes to break the shell

Question 10

what influences shell thickness

Answer 10

• inheritance - specific breeds have different shell thicknesses
• nutrition - calcium, phosphorus, vitamin D manganese and zinc, cation-anion chloride (if nutrition is suspected check the feed)
• disease (infectious bronchitis - very weak shell
• environmental temperature - reduced feed intake , increase CO2 loss

Question 11

what influences cracked eggs

Answer 11

• influencing factors = thin weak shells, age of birds (0.5% increase each aged month)
• management practices = frequent gathering, rough handling, improperly adjusted equipment and slope of cage/nest floor

Question 12

what happens to large eggs from older birds

Answer 12

• larger eggs but weaker shells = because calcium is spread over a larger area

Question 13

what is a body check

Answer 13

• a crack right down the middle = something scares the bird, stops calcium around the biggest roundest part and starts again when the bird is calm = the middle section of the bird is weak

Question 14

what factors influence shell cleanliness

Answer 14

• bird housing - density
• nature of housing - type (enriched, conventional, free run))
• housing design
• clean housing and equipment (good vs bad management)
• GI disease - diarrhea = dirty eggs

Question 15

what can albumen quality tell us about the egg

Answer 15

• egg quality
• measure the thickness

Question 16

what is albumin quality measured in

Answer 16

haugh unit
- takes the weight of teh egg into account

Question 17

what factors influence albumen quality

Answer 17

• egg storage conditions (temperaure- the longer they are stored the more they break down, they also break down slower in colder temperatures)
• health of the flock (infectious bronchitis)
• egg oiling - this oil layer that covers the eggs and prevents them from drying out
• nutrition - vanadium contamination of phosphorus
• inheritance

Question 18

what does the yolk colour relate to

Answer 18

related to the dietary carotenoid pigment content (corn, grass and grasshoppers)

Question 19

what is a mottled yolks

Answer 19

• diffusion of the membrane into the yolk ( more common in stored eggs because the membrane breaksdown in the fridge)
• primarily due to diffusion of factors from albumen to yolk
• factors influencing (feed additives, disease and egg handling)

Question 20

what causes hard yolks

Answer 20

• maybe fatty acids but we arent sure
• weed seeds containing unusual fatty acids may be responsible

Question 21

what causes blood spots

Answer 21

• rupture in blood fessel in follicle
• ovulation in area other then stigma (breaksdown at a different spot then teh center)

Question 22

what factors can influence blood spots

Answer 22

• nutrition (vitamins A and K
• inheritance
• production stage

Question 23

what causes meat sports

Answer 23

• brownish or whitish spots in egg
• degenerated blood, pieces of shell, sloughed tissues from from oviduct

Question 24

what other abnormalities can occur and why do they occur

Answer 24

• double yolks- ovulations on the same day and the places a shell around both
  yolkless - something signalled to make an egg even though there wasnt ovulation

Question 25

how are eggs kept from breaking

Answer 25

- frequent gathering of eggs (prevent damaging and breakage) - storage ( 4-7 days and 1-2 days for large companies) - temperature - 5-10C to prevent breakdown of egg white down - relative humidity - 70-80% dehydration - clean conditions

Question 26

what is oiling

Answer 26

- use of odourless, colourless mineral oil to seal shell pores and maintain albumen quality - not used in north america ( fridge storage and egg turnover)

Question 27

what are the steps of egg processing

Answer 27

- small number of egg processors - step 1= washing, high pH solution to eliminate bacteria, all eggs are washed, not in europe - step 2 = candling, ultrasound, eliminate blood spots, meat spots, double yolks and abnormal shapes, detect cracked eggs - step 3 sizing - each egg is weighed and sorted - step 4 - placed on eggs in cartons based on size

Question 28

how are eggs graded

Answer 28

- shell quality - interior quality

Question 29

what are you looking for in a shell quality egg check

Answer 29

- cleanliness - soundness - shape

Question 30

what are you checking for in interior quality checks

Answer 30

- eggs are candled to determine interior quality - air cell size - as CO2 and H2O leaves over time and air cell gets larer - distinctiveness of yolk - albumen gets thinner and the yolk begins to sink

Question 31

how can storage change egg quality

Answer 31

- moisture loss = decrease egg weight, increase air cell size - loss of carbon dioxide = change in egg pH (7.6-9.5) - albumin thins = ovomuchin degration and lyzozyme involvement - yolk enlargement - because the membrane breaks down and spreads out - loss in flavour

Question 32

what is an egg breaker

Answer 32

- eggs are broken by machine and the shells and chalazae separated from albumen and yolk - egg products are pasteurized and then prepared to be sold in various forms

Question 33

what products are produced from egg breakers

Answer 33

- liquid = yolk, albumen, ready to cook egg products - frozen - dried - specialized products - lysozymes - antimicrobial can be used for humans as antibiotics - immunoglobulins - antibiotics - human medicine - vaccines

Question 34

what vaccines are created from eggs

Answer 34

- eastern equine - rabies - influenza - mumps - canine distemper - yellow fever