Public health, meat science and zoonosis Flashcards
What is a transboundary animal disease and provide some examples ?
Transboundary disease (TAD)
Defined as a disease of significant economic, trade or food security importance for a number of countries which can easily spread to other countries and reach epidemic proportions.
Transboundary diseases are highly transmissible or contagious, epidemic diseases with the potential to spread rapidly.
Examples
- Foot and mouth disease (FMD)
- African swine fever (ASF)
- New Castle disease
- bovine spongiform encephalopathy
Why are TAD significant to trade ?
Transboundary disease (TAD)
significance to trade ?
Risk of loss of International trade of the affected animals and their products
What three organisations cooperate and interact to ensure the safe international trade of animals and their products ?
Organisations
World trade organisation (WTO)
WOAH (world organisation for animal health)
Codex Alimentarius
Give some examples of zoonotic diseases that are notifiable in human medicine ?
Zoonoses notifiable if they are diagnosed in humans.
- Anthrax
- Avian influenza
-Brucellosis
- Hendra virus
- Leptospirosis
- Rabies / lysavirus
- Palgue
- Q fever
Define food safety / food hygiene ?
Food safety = Assurance that food will not causes harm to the consumer when it is prepared or eaten according to its intended use.
Food hygiene = Assurance that food is acceptable for human consumption according to its intended use.
What is inspection ?
Inspection means = examination and evaluation of animals, and animal products by an authorised person (Veterinarian?) prior to completing a certificate to document the health or sanitary status.
What is certification ?
Certification
= means an official document completed by an authorised Veterinarian for purposes of verifying the health status of animals and safety of animal products (sanitary status)
What is the purpose of WOAH (OIE) and CODEX (Alimentarius) ?
Woah, CODEX Alimentarius and WTO
The safe international trade of animals and their products relies on the interaction between and cooperation of the above organsiations.
Explain your definition of Veterinary public health (compare with later on in the course) ?
Veterinarian contribution to the physical, mental and social well being of people through an understanding and application of Veterinarian Science.
Why is food safety central to the Veterinary profession (mixed and large animal practice) ?
We wouldn’t have a job if safe products could not be produced by animals ?
Why is prevention so important in Veterinarian medicine ?
Prevention is key
- reduce the need to treat animals (improving welfare)
- fewer treatments
- less antimicrobial resistance
fewer residue issues
What is the public health significance of incorrectly splitting a bovine carcass down the dorsal midline ?
Human health risk
Prion protein causing bovine spongiform encephalopathy (BSE) - found within the nervous tissue of cattle.
- exposes work personal to nervous tissue of cattle
Please define WHO, WOAH, FAO and FSANZ ?
Definitions
WHO = world health organisation
WOAH = World organisation for human health
FAO = Food and Agricultural organisation of the United Nations
FSANZ = Food standards Australia New Zealand
What is the WHO - FAO definition of VPH ?
WHO FAO definition of VPH
Veterinary public health =
The sum of all contributions to the physical, mental and social wellbeing of humans through an understanding and application of veterinary science.
What is global health and how is it relevant to Veterinary science ?
The relevance of global health
Global health = An area of study, research and practice that prioritizes improving health and achieving health equity for all people worldwide.
Veterinarians are critical contributors to global health
For example
- toxoplasmosis
- antimicrobial resistance
- covid 19
What is the role of FSANZ ?
Food standards Australia New Zealand
Their role is to set the food regulations in Australia and New Zealand
- ‘risk factor’ preferred
What are the four steps of a risk assessment ?
The four steps of a risk assessment
- Hazard identification
- Hazard characterisation
- Exposure assessment - likely hood of exposure
- Risk characterisation - likely hood adverse effect
Discuss with examples the categories of hazard that we mainly use in Veterinary Science ?
Generally categorised as one of five major types
Biological hazards - bacteria, viruses, prions
Chemical hazards - environmental residue, naturally occurring toxins, allergens
Physical hazards - broken needles, bite / scratch, back injury
Discuss, with examples how VPH is relevant to a Veterinary practitioner’s everyday role, Consider physical / social and mental wellbeing ?
VPH relevance to Vets everyday role
Physical well being
- zoonosis, insuring standard compliance at abattoir, vaccination of animals, worming of dogs, pet advice eg dangerous dogs
Mental well being
- health of our pets
- upkeep of welfare standards
Social wellbeing
- dog neuter spay assisting of the community
- setting community recommendations from a professional viewpoint
eg wilds dogs and farmed goats people out of business
Discuss with examples how VPH is relevant to a Veterinarians practitioners every day role ?
Every day task of a veterinarian impacts
Human mental health - pet health
Human social health - community expectations
Human physical health - advice on worming, vaccination
Discuss the added benefit criterion of a one health approach ?
It’s in the definition
One health is defined as an added benefit achieved through different professional s working together.
Define the term meat, and meat quality ?
The definition of meat =
The muscles and associated structures (skin, bone of animals, birds and mammals) consumed for food.
- due to TSEs neurological tissue is excluded by official definitions
- usually dose not include fish
Meat quality =
Meat quality is usually defined as a measurement of attributes or characters that determine the suitability of meat to be eaten as fresh or stored for a reasonable period without deterioration.
“what doesn’t kill you makes you stronger”
A more encompassing definition
“Quality has been defined by the set of attributes that allow the product to satisfy end user needs, which cover organoleptic, nutritional, safety, commercial, technological and image attributes”
+ consistency and predictability eg maccas
Describe the five pillars of consumer demand when it comes to meat quality ?
Consumer notion of quality is more than a nutritional value, durability and safety. Meat is more than just a food.
The notion of meat quality is inherently subjective
It can be quantitatively; what am I prepared to pay for the “joy” of eating meat above and beyond its nutritional value.
- organoleptic experience
- perceived healthiness and safety (no contaminants, residues or bugs)
- peripherals such as provenance, ethical production and food miles.
- strong preference for what is considered natural (no feed lotting + grain fed perceived as less flavourful) - EMBARGO feeding issue?
- produced without antibiotics, hormones or partitioning agents. (some QA programs demand no AM ? Is this ethical)
- lean product perceived as healthy
So immediately there are conflicts that produce compromise or perhaps consumers are ignorant or even prefer to ignore.
For example by any measure grain fed beef is inferior to grain fed.
- tenderness, flavour (role of intramuscular fat),
There are enormous cultural, religious and socioeconomic variations on the general theme.
What is organoleptic mean ?
Organoleptic
The aspects of food as experienced by the senses taste, sight and smell
- taste, tenderness, appearance and smell
When it comes to meat what does the processor need ?
The processor demands
- A high carcass yeild
- They are after animals on the grid
- weight
- weight and fat score
- weight fat score and other things - Clean product that ensures good provenance of the product.
Greenham’s never ever beef program
Describe what a meat producer is looking for to maximise profit, and what tools are available for him to utilise ?
What dose the producer want
Kg/lamb/beef over the first limiting resource usually hectares but may be some other limiting resource.
- meet consumer end user demands
A producer may choose to target specific markets to suit his production system and its limitations
eg Southern producer = QA domestic market , Northern producer = finish to specs required for the American ground beef market
Tools the producer can utilise
- genetics (GBVs and EBVs)
- environmental management
- stock handling, atraumatic handling, transport management and pre conditioning.
What is involved in converting meat to muscle ?
Muscle to meat
We hardly ever if ever eat fresh harvested meat “say within 3 hours of slaughter”
Converting muscle to meat has three phases. How the meat is handled can affect meat eating quality and safety profoundly.
- Cessation of metabolic function of the muscle
- Onset of rigor mortis
- Relaxation of rigor mortis by proteolysis
Describe the process of cessation of muscle cell metabolic activity ?
Cessation of muscle cell metabolic activity
At the most basic muscle cell “life” and contractility depends on energy provided by ATP to AMDP or AMP.
ATP levels are maintained by too processes oxidative phosphorylation requiring 02 and glycolysis which utilise anaerobic pathways.
The glycolytic pathways are contingent on muscle cell stores of glycogen. As glycogen is depleted
the muscle PH drops from >6.5 living muscle to <5.7 in meat.
The overall drop in PH and temperature and background in which this drop occurs is primary driver of meat quality.
The muscle glycogen content at the time of death is a major determinant of the PH drop and its speed.
Describe the process of rigor mortis ?
Muscle to meat process rigor mortis
Rigor mortis is the process of individual muscle fibres entering the contracted state. Rigor mortis is when the whole carcass has entered this state.
- this is contingent on the glycogen reserves and temperature of each muscle group.
- as glycogen depletes there is no restoration of ATP and thus muscle activity stops
- Muscle relaxation is dependant upon ATP. Without ATP muscle enters the contractile state where actin and myosin are strongly bound.
Time 4-24 hours
dependant upon temperature, carcass size and species.
Describe the process of proteolysis, meat tenderising and meat aging ?
Proteolysis, meat tenderising and meat aging
Carcasses in the rigor state have no utility - difficult to handle and tough.
Resolution of rigor occurs due to the action of endogenous enzymes
-Calpains and cathepsins (calpains more important in red meat).
- cause proteolysis of the myofibril, but do not break down the actin myosin bond. Only small changes in the collagen components
- Interspecies differences in the rate of proteolysis affect time to final eating state and overall tenderness.
- Calpain antagonist (calpastatin) may result in intraspecies differences
- big differences in processing cost due to aging times
Identify the organisations who oversee meat quality ?
Who oversees meat quality
Ausmeat
Is a NFP corp set up between the Australian meat processors corporation and meat and livestock Australia
- manage red meat trade description
- accredit domestic processors, audit, train
Meat standards Australia (MSA)
The MSA was developed by the red meat industries (lamb, beef) to provide a rating system for consumers to easily identify consistent quality products.
- grade beef and lamb via organoleptic qualities tenderness, taste, juiciness, overall eating experience
Food standards Australia and NZ (FSANZ)
- Federal independent statutory authority that governs standards for ingredients, composition, standards, labelling and standards for new technologies.
FSANZ works to the standards of codex Alimentarius (FAO)
Meat colour is one determinant of meat quality. What determines meat colour ?
Meat colour
There is a strong preference for a cherry red colour
MSA IB - 3 inclusive
What determines the meat colour
The colour of meat is almost completely determined by the myoglobin content.
- species/animals with a greater reliance on aerobic muscle have more colour due to larger amount of myoglobin.
chicken < pig < lamb < beef
- diet iron concentration and supplements
Types of MB and their effects on meat colour
Fe2+ ferrous state cherry red colour
- exposure to CO or O2 causes meat to bloom
Fe3+ ferric state colour
- Fe3+ is a result of oxidation undesirable and indicative of deteriorating meat quality.
Describe the factors which would favour a ferrous state within meat ?
Factors which favour a ferrous state within meat
- Oxygen
A high oxygen environment or CO favours the ferrous state - Lipid content and use of antioxidants
VIT E supps effectively favours the ferrous state - Bacteria up to 10*8 CFUs
- Light
Tends to oxidise oxidise MB but some wavelength are better than others. (LEDS may be best) - which muscles are involved
Define dark cutting DFD meat, and what it results from ?
Dark cutting
Dark cutting or dry/firm/dark DFD is a fault of the beef and to lesser extent lamb and pork.
It results from low muscle glycogen limiting the drop in PH after slaughter. Instead of dropping to <5.7 by the time of rigor meat >6 at the time of rigor.
The high PH results in
- retention of darker pigments
- greater water holding capacity + and hence a dry firm and sticky surface
- high water holding capacity may be good for meat processing, but consumers think of it as a sign of unhygienic / or spoiled meat.
What to do
Maintain muscle glycogen, or restore it before slaughter
- atraumatic stock handling
Long haul transport and rough handling reduce glycogen content
- nutrition
High energy feeds that favour propionate formation also favour the storage of glycogen. (grain fed or supplemented beef) or green actively growing pasture aim for 65% digestability.
-
What would you advise a producer whos’ animals are being processed DFD ?
What to do with DFD Dark/firm/Dry
Maintain muscle glycogen, or restore it before slaughter
- atraumatic stock handling
Long haul transport and rough handling reduce glycogen content - nutrition
High energy feeds that favour propionate formation also favour the storage of glycogen. (grain fed or supplemented beef) or green actively growing pasture aim for 65% digestibility. - cull out animals with a poor temperament
- Do not mix mobs immediately prior (last two weeks before slaughter)
The time in lairage
- short intervals may allow some repletion of glycogen post travel
- long periods (>12 hours) are likely to make the situation worse / stress.
What is PSE and what is it determined by (meat) ?
PSE = Pale Soft exudative = pork / chicken
PSE pork results from acute stress close to slaughter
Pathogenesis
Glycogen utilization immediately before slaughter causes a PH drop at higher temperatures than normal.
This leads to
- protein denaturization
- low water holding capacity, bound water is released
- muscle fibre separation
Hence soft and exudative, pale comes from early oxidation from Fe2+ to Fe3+.
May be affected genetically porcine stress syndrome or Hal mutation in the RYR gene.
What would your advice be to reduce the incidence of PSE ?
How to reduce PSE pale soft exudative
Management measures
- Reduce immediate preslaughter stress. This is a processing plant issue
- Speed of operation
- Conveyor belts and gentler options
- No use of goads or excessive handling
What do consumers prefer with reference to carcass fat, how do we obtain this ?
Fat preference - fat determines texture
The consumer prefers firm, white fat.
The amount will be contingent on the carcass characteristics, excess fat may be trimmed.
Monogastric - The composition deposited in the carcass reflect what is in the diet. (high unsaturated fat in diet = high unsaturated fat in the carcass
Carcass high unsaturated fat
- unable to hold shape
- low fat melting point and greasy feel to handle.
In ruminants; most unsaturated dietary fat is saturated during digestion. Thus firm white fat is not generally an issue. (exception high clover for lambs produces more PUFAS; softer fat less desirable cooking smell).
Fat colour which is influenced by
- Grass fed vrs grain fed ((carotenes in grass can cause yellow discolouration)
- Breed (jersey yellow)
- bco2 genes B carotene oxygenase in sheep meat breeds produces carotene accumulation which may lead to carcass condemnation. Sennin a low frequency within british breed sheep.
What factors determine the juiciness and water holding qualities of meat ?
Juiciness and water holding
Juiciness is one of the main organoleptic components of palatability.
Def = Impression of moisture and lubrication when meat is chewed.
Perception of juiciness depends upon
1. Moisture in the first few chews
This is dependant on water holding capacity
2. Perceived moisture succulence after continued chewing
This depends upon intramuscular fat aiding ease of chewing and stimulating saliva production
Therefore juiciness/ succulence depends on WHC (water holding capacity) and IMF (intramuscular fat)
