Eqq Quality and Processing Flashcards
1
Q
what is the yolk
A
- blastoderm (fertile) or germinal dis (infertile)
- vitelline membrane (protein)
2
Q
what is the albumen
A
- 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
3
Q
what is the structure of the egg
A
- 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
4
Q
what do each of the shell membranes do for the egg
A
- one stays on the shell
- one detaches and creates the air pip
5
Q
what does the cutical do for the egg shell
A
- stops bacteria and dehydration
6
Q
what is a cutical
A
- 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
7
Q
what influences egg size
A
- 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
8
Q
what influences egg shape
A
- 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
9
Q
how can you measure egg shell thickness or strength
A
- 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
10
Q
what influences shell thickness
A
- 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
11
Q
what influences cracked eggs
A
- 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
12
Q
what happens to large eggs from older birds
A
- larger eggs but weaker shells = because calcium is spread over a larger area
13
Q
what is a body check
A
- 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
14
Q
what factors influence shell cleanliness
A
- 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
15
Q
what can albumen quality tell us about the egg
A
- egg quality
- measure the thickness
16
Q
what is albumin quality measured in
A
haugh unit
- takes the weight of teh egg into account
17
Q
what factors influence albumen quality
A
- 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
18
Q
what does the yolk colour relate to
A
related to the dietary carotenoid pigment content (corn, grass and grasshoppers)
19
Q
what is a mottled yolks
A
- 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)
20
Q
what causes hard yolks
A
- maybe fatty acids but we arent sure
- weed seeds containing unusual fatty acids may be responsible
21
Q
what causes blood spots
A
- rupture in blood fessel in follicle
- ovulation in area other then stigma (breaksdown at a different spot then teh center)
22
Q
what factors can influence blood spots
A
- nutrition (vitamins A and K
- inheritance
- production stage
23
Q
what causes meat sports
A
- brownish or whitish spots in egg
- degenerated blood, pieces of shell, sloughed tissues from from oviduct
24
Q
what other abnormalities can occur and why do they occur
A
- 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
25
Q
how are eggs kept from breaking
A
- 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
26
Q
what is oiling
A
- use of odourless, colourless mineral oil to seal shell pores and maintain albumen quality
- not used in north america ( fridge storage and egg turnover)
27
Q
what are the steps of egg processing
A
- 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
28
Q
how are eggs graded
A
- shell quality
- interior quality
29
Q
what are you looking for in a shell quality egg check
A
- cleanliness
- soundness
- shape
30
Q
what are you checking for in interior quality checks
A
- 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
31
Q
how can storage change egg quality
A
- 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
32
Q
what is an egg breaker
A
- 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
33
Q
what products are produced from egg breakers
A
- 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
34
Q
what vaccines are created from eggs
A
- eastern equine
- rabies
- influenza
- mumps
- canine distemper
- yellow fever
