Poultry and egg production Flashcards
Main constituents in eggs
Protein, fat, water
Describe the anatomy of an egg
Component - eggshell
CaCO3 crystals - semipermeable membrane - cuticle
Describe air cells
- grows larger with age - important for fertilised eggs
Describe albumen
contains approx 40 different proteins main components of egg white in addition to water
Describe chalaze
opaque ropes of eggwhite, the chalaze holds yolk in centre of egg
Describe yolk
less water and more protein than the white, some fat, most of the vitamins and minerals of the egg
Describe class A eggs
a. shell and cuticle: normal shape, clean and undamaged b. air space: height not exceeding 6mm, stationary, however for eggs to be marked as ‘extra’ if may not exceed 4mm c. yolk: visible on candling as a shadow only, w/o clearly discernable outline, slightly mobile upon turning the egg, and returning to central position d. white: clear, translucent e. germ: imperceptible development f. foreign matter: not permissible g. foreign smell: not permissibile - SHALLOT BE WASHED OR CLEANED, before or after grading (no exceptions in UK)
Describe class B eggs
eggs are broken out and pasteurised
Describe Class industrial eggs
industrial eggs which are for non-food use only and are used in products such as shampoo and soap
Explain the different parts of the egg lion mark
Describe egg pasteurisation
- legislation requires egg to be heated to 64.4 degrees for 2.5 minutes (kills most bacteria) - destroys all pathogens w/o affecting any of the good qualities of the egg - egg is cooled to below 4 degrees then packed
What is the difference b/w white and brown eggs?
- brown hens (prone to cannibalism, popular in UK, why beak trimming is employed, banned from Jan ‘16) –> brown eggs - white hen (USA, not prone to cannibalism) –> white eggs
Food safety risks of eggs
- salmonella - campylobacter
Describe salmonella in eggs
- Salmonella enteritidis and Salmonella typhimurium - rod-shaped gram negative bacterium belonging to enterobacteriaceae - transmitted by rodents and wild animals
Outline salmonella pathogenesis
- usual route of infection in enteritis is faecal-oral although infection through upper RespT and conjunctiva reported - colonisation of digestive tract and invades and multiples in enterocytes and tonsillar lymphoid tissue - attachment through fimbrial Ag - gut damage and diarrhoea
Outline salmonella control
2 national control programs *laying and broiler
Salmonella control - broilers
- samples taken at chick placement - samples taken within 3 weeks of first birds being sent for
Salmonella control - layers
- test as day olds - test within 2 w of lay before transfer to laying farm - every 15 weeks (first test within 22-26 weeks) - someone walks round house and sends off clothes to lab for testing
Describe campylobacter
- C. jejuni - gram negative but considered thermophilic, obligate and microaerophilic bacterium that is ubiquitous in temperate environments - birds have a higher body temperature than mammals, Campylobacter particularly suited to colonise them - colonises themucous overlying the epithelial cells in the gut - reduction achieved through multiple intervention strategies - each time a carcass is treated in a way that physically removes Campylobacter (suction but risk of rupture of GIT and crop) or chemically kills campylobacter (NOT in the UK) –> reduced #
List primary production interventions to reduce campylobacter
- investigate efficacy of biosecurity interventions - hygiene barriers, fly screens and water tx (once/w) - review rapid on-farm capylobacter test - investigate motivational drivers of biosecurity compliance - TRANSPORT INTERVENTIONS: investigate/trial crate washing, improved crate drying and novel crate and module disinfection methods - PROCESSING INTERVENTIONS: UK trialling lactic acid wash in turkey and chicken processing (USA uses chemicals, UK also trialling sonar), trial new water spray washes and rapid chilling method washes in slaughterhouse - RETAILERS: trial leak-proof packaging for chicken products, investigate impact of modified atmosphere packaging techniques, consumer education, research to understand consumers’ attitudes to potential interventions and consumer behaviour, review of on-pack best practice instructions on storage, handling, preparation and cooking for consumers on chicken products - CATERING: address issue of undercooked liver pate and parfait, develop a best practice compliance toolkit and refresher education programme via Safer Food, Better Business programme.
