Egg Hygiene Flashcards
What are the top 4 producers of eggs?
- China
- India
- Indonesia
- USA
Where does egg formation begin?
ovaries - begins as a yolk by the rapture of follicles to release
What are the 5 places in the female reproductive system that develops the egg?
- infundibulum - yolk, sperm fertilization
- magnum - albumin
- isthmus - shell membrane, shape determined
- uterus (shell gland) - albumin, shell, cuticle pigment
- vagina/cloaca - egg is laid (egg has pores and can be contaminated)
When are hens able to lay eggs? How long does this take?
4-5 months
25 hours - lays an egg every 25 hours from 4-5 months to 18 months
What are the 3 major structures of eggs and their proportion?
- shell - 11%
- albumin (egg white) - 58%
- yolk - 31%
What makes up the egg shell? Why are eggs prone to contamination if they have a shell?
calcium carbonate
has small pores —> Salmonella commonly makes it through
What is the shell membrane? Air cell? Chalazae?
membrane that covers the albumen
formed by contraction of the contents of the egg during cooling and loss of moisture (not present in freshly laid eggs)
twisted cords that keep the yolk suspended in the albumin at the center of the egg
What is the vitelline membrane? Germinal disc?
membrane encapsulating yolk
part of the yolk where fertilization takes place
What is yolk rich in? Why?
high cholesterol = concentrated food for embryo if egg is fertilized
What are the major chemical compositions of eggs? Which are especially high in shells, albumen, and yolk?
- water = 77%
- protein = 12%
- lipids = 10%
- carbohydrates = 1%
SHELLS = minerals
ALBUMEN = protein (fat-free)
YOLK = lipid (fat)
What are the 2 major sources of egg contamination?
- microbes in reproductive tract before the shell forms around the yolk and albumen (vertical transmission) - Mycoplasma, Salmonella pullorum
- bacteria on the shell due to cloacal opening - enteric bacteria and viruses (Salmonella)
What bacteria are the most common bacterial pathogens affecting eggs?
- Salmonella***
- Mycoplasma
- E. coli*
- Chlamydia*
- Campylobacter*
- Coryza
- Ornithobacterium
- Gallibacterium
- Spirochets
What viruses are the most common viral pathogens affecting eggs?
- Infectious Bronchitis virus
- Avian Influenza virus
- Newcastle Disease virus
What syndromes commonly result from egg contamination?
- egg drop syndrome
- swollen head syndrome
- avian encephalomyelitis
- laryngotracheitis
- fatty liver hemorrhagic syndrome
- cage layer osteoporosis
What are the 9 steps eggs take farm to consumer?
- production
- collection
- cleaning
- sorting and handling
- grading
- packaging
- processing
- storage (refrigeration)
- distribution and shipping
In what 2 ways are eggs collected and harvested? How many times a day? Why?
- automated egg collection system
- manual egg collection
4-8 days —> lessen chances for contamination of eggshells from nesting material and hens and ensures minimal and uniform levels of pre-incubation
Shelled eggs processing:
What are 5 common compounds used for egg washing and sanitizing?
- chlorine
- quaternary ammonium compounds
- peracetic acid
- PAA with UV light
- hydrogen peroxide with UV light
What are the 2 types of criteria that eggs are inspected and sorted upon?
- egg safety - exterior quality, interior quality
- egg grading - freshness, size/weight
What are the 3 possible anatomical defects of eggshells?
- intact
- broken, but not leaky = check
- broken and leaking = leaker
In what 3 ways is eggshell cleanliness scored?
- slight stain - AA or A
- moderate - B
- prominent/soiled
Why is eggshell quality inspected?
shell defects and contamination leads to rotting
What is candling? What are 2 advantages of doing this?
process of using light to detect eggs with cracked shells and interior defects/quality
- detect and segregate defective eggs
- determines price of egg based on grade
What are 2 common yolk defects? What causes each?
- pale - alfa toxin B1, worm infestation
- stuck - chalazae breaks and causes yolk to stick to the eggshell
What are 3 common albumen defects? What causes each?
- decline in content
- green - bacteria and fungal contamination
- bloody - vitamin deficiency, mycotoxins
What are some common overall egg color, odor, and consistency quality changes?
- large spots due to vitamin deficiencies or mycotoxins
- cooked
- frozen
- blood ring
- sour, black, mixed rotting
- moldy
What 2 criteria is egg grading based on? Is this mandatory?
- egg size
- egg structure
no —> inspection is necessary to compare wholesomeness, but grading for quality is voluntary
What are the 5 grades of eggs based on size?
- small - 18 oz
- medium - 21 oz
- large - standard 24 oz
- x-large - 27 oz
- jumbo - 30 oz
increases in calorie, fat, and protein content with size
What are the 3 consumer grades for eggs in the US? What factors affect this?
- Grade AA
- Grade A
- Grade B
yolk, albumen, air cells, shell
How does the eggshell quality compare with grade?
- AA: clean, unbroken, polished
- A: clean, unbroken, not as polished
- B: clean or slightly stained with an abnormal shape
How does air cell space compare with grade?
- AA: no more than 1/8 an inch
- A: 1/8 to 3/16 inches
- B: larger than 3/16 inches
(decreased air space with better grade)
How does albumen compare with grade?
- AA: firm, thick egg whites that elevate yolk
- A: less firm egg whites
- B: flat yolk and thinner egg whites
How does yolk compare with grade?
- AA: slightly defined
- A: outline more defined
- B: outline clearly defined
What governmental agencies take part in grading eggs? What are each used for?
- AA and A: USDA FSIS, frying and poaching
- B: FDA, broken and processed to make liquid, frozen, and dried egg products
What are 5 types of eggs unsafe/unsuitable for human consumption?
- contaminated with feces
- broken/leakers
- bacterial or fungal rots
- incubator eggs
- stored for hatching for a sufficient time
Broken egg process:
What are the 2 main methods of egg decontamination before/during egg processing?
- chemical - washes eggshell with chlorine, quaternary ammonium, calcium/sodium hypochlorite, iodine, radioactive cobalt 60
- thermal - pasteurization (>64 C), refrigeration (<5 C)
What accounts for most egg-borne pathogens?
Salmonella
What are the 6 major egg safety rules in the US?
- remove egg with defects from egg supply chain - checks, leakers, dirty, inedible, loss
- refrigeration
- pasteurization of broken eggs
- Salmonella enteritidis testing
- control S. enteritidis using biosecurity, cleaning, disinfection, fly/rodent control, testing, refrigerations
- GHP inspection and HACCP
