must know Flashcards
Sterilization =
• No aerobic or microaerophilic bacteria can grow on culturing media used in medical bacteriology,
Disinfection =
- Eliminating/destroying infective and facultative pathogenic microorganisms by substances known to have disinfective capacity.
- Freeing from pathogenic organism, or rendering them inactive
Factors affecting efficiency of disinfection:
Biological factors • Survival of germs • Resistance to disinfection o Technological factors • All in all out • Value of service period of cleaning disinfectant
gama rays function:
causing irreversible destruction in structure of proteins and DNA
W-rays (lamps) function:
- Changes DNA = wear protective glasses and clothes
* Only for disinfection of dust free surface (limited value) = Photooxidation - Two compounds
Disinfection of stables steps:
- Removal of equipment and dry cleaning
- Pre-cleaning → wet wash with appropriate detergents
- Sanitizing and disinfecting the water system → Header tanks, drinkers, pipelines
- Movable equipment
- disinfection
- Fogging and aerial disinfection
Disinfection of vehicles
• Dry cleaning • Cleansing and rinsing • Disinfection • Cab disinfection Finally → park on a slope to drain and dry, remove vehicle, wash concrete surface with appropriate disinfectant, then disinfect overalls and boots.
Disinfection of wells
- 30 g/m3 chlorine powder
* 100 ml/m3 sodium hypochlorite Monitoring the
efficiency of disinfection, how to check:
- Direct swabbing technique
- Agar cylinder techniques
- Agar sausage method
- Agar-carrying linen
- Ready to use test
Physical methods of sterilization/disinfection:
- Heat
- irradiation
- UV light
- Other Physical Methods
• Ultrasonography (Gr -)
• High pressure (Gr-/+)
• Microwaves - only vegetative form
Biological Methods of sterilization/disinfection:
Feedstuff/Manure fermentation
• Competition
• Antimicrobial metabolites
• Changing environment (E.g. silage)
Chlorine based compounds:
- general properties
- example of compounds
▪ Room temperature → toxic gas
▪ Water soluble
▪ Penetrates cell membrane, destroys cellular enzyme with SH- radicals.
▪ increased temperature reduces capacity
▪ Organic materials decrease capacity
▪ Corrosive!
- NaOCl
against → vegetative bacteria + all viruses, but no acid fast bacteria or spores - Chlorinate lime – bleach
Disinfectant of wells, other water resources and surfaces (roads)
Iodine based compounds
- basic function
- colour
- example of compound
▪ Iodophores → iodine + organic substrate (surface active materials)
● + phosphoric acid → solubilising the iodine (detergent)
● + buffers → ↓ pH
● + polyvinyl-pyrolidine → bind up to 30% of iodine
→ oxidizes function groups of germs
▪ Colour → dark brown to light yellow
▪ Surface friendly and powerful cleaning effect due to detergent content
- Betadine (pavidone-iodine)
- Advantage → Bactericidal, viricidal, fungicidal
- Disadvantage → skin sensitive, partially inactivated by organic debris
Aldehydes
- spectrum
- genral properties
- not mixed with….
- forms:
• Efficient, broad spectrum
• -CHO- radicals → destroy cell wall
• Formaldehyde
1. Formalin: = Used in solution and gas form for surface disinfection
2. Irritant, odorous, suffocating, cough evoking, colourless gas
3. Attacks all mucous membranes
4. No hindering by organic materials
5. Formaldehyde gas or water solution
• May be neutralized with NH3
• Safety → not to mix with NH4 solution, H2O2, Heavy metal solutions
6. Paraformaldehyde
• White, crystallized, smelly powder, Gas disinfection of smaller stables
7. Glyoxal
8. Lysofom
Peroxide based compounds
- main properties
- compounds ant their characterisitcs
• Deliberates mono atomic oxygen → destroys membranes and organic molecules of bacteria
- Hydrogenperoxide
= Colourless, odourless, aggressive, mildly acidic liquid → decomposes quickly.
- Strong corrosive → pure form is not used.
Disinfection of utensils in 3-10% concentration - Peroxy acids
= Formic and acetic acid.
Also may contain phosphoric acids and stabilizers - Peracetic acids
= Aggressive fluid with vinegar like odour.
Food industry and production of SPF animals → wide antimicrobial effect, quick decomposition after use. Not to be used with alkalis
Surfactants (tensides)
- general properties
- groups
• Water and alcohol solution → reduces surface activity surfaces, helps remove dirt, enhances efficiency of
other disinfectants
- Anion active tensides (alkali sulphates, soaps) = Strong lipid solvent. No disinfective capacity
- Cation active tensides (sterogenol, Bradophen-H)
= Disinfectant capacity.
Decreases surface activity of cell membrane and increases its permeability.
- Efficiency decreased by hard water - Non ionic tensides (TWEEN 80) = Do no dissociate in solutions. Mild disinfection capacity, often in
combination - Ampho-tensides (acidic and alkali groups)
= Acidic surrounding → as cationic active tensides. Basic surrounding → as anionic tensides
Acids and alkalis
- groups, examples and properties
- Inorganic acids → nitric-, hydrochloric-, sulphuric-, phosphoric acids: Strong corrosives, not used
- Organic acids → formic-, lactic-, malonic-, glutamic-, propionic acids: Used in combination with other
disinfectants, especially with anionic tensides. Increases virucidic and sporocidic action - Alkalis → NaOH, KOH : Were used by dairy industry. Hot solution in 2-4% concentration → bacteria and
viruses. Hot solution in 6% concentration → sporocide. Strong corrosive effect
Miscellaneous
- groups, examples and properties
- Phenols and cresols → virucides and sporocides, extremely toxic, pollute environment
- Alcohols → based on water extraction, Gr+ and vegetative bacteria, used in combination (skin)
- Others → glycols, guadinins
Gaseous disinfectants:
- examples
- general properties and uses
(=gas state at room temperature)
- Etyhlene oxide
= Sweet ether like smell.
- Good penetration → paper, cellophane, plastic containers.
- Attack –SH, -amino, -carboxyl and hydryl radicals of proteins.
- Strong bactericide, virucide and sporocide. - Inflammable / explosive.
Inhalation → headache, nausea, mucosal irritation.
Uses → textile, containers, feed - Beta propionlactone → gas sterilisation
- Methyl bromide → insecticide
Effects of animal production on the nature and society
- Harmful emissions → greenhouse effect, damage ozone layer, damage life quality, transmission of
diseases, acid rain (soil acidification) - Pests → rodents, birds, insect
- Animal wastes → soil and water pollution, infections
- Food safety and quality → direct effects, indirect effects
- Effects on animal health → reproductive failures, management related diseases
- Labour health
Definition = Animal wastes/byproducts →
entire bodies or parts of animals or products of animal origin not intended for human consumption, including ova, embryos and semen.
SRM I =
- Head without the tongue, thymus, spleen, spinal cord of bovine animals over 6 months, and the intestines (duodenum → rectum) of bovine animals of all ages
- Skull including brain, eyes, tonsils, spinal cord of bovine animals over 12 months.
- Vertebral column including dorsal root ganglia of bovine animals over 30 months.
• SRM II =
• Skull and brain, eyes, tonsils and spinal cord of ovine and caprine animals over 12 months or which have a permanent incisor erupted through the gum, and the spleen of ovine and caprine animals of all ages
Catergory I materials:
a. All body parts including hides, skins of:
• Animals suspected of being infected by TSE or the presence of TSE has been confirmed
• Animals other than farm animals and wild animals
• Pet animals, zoo animals, circus animals
• Experimental animals
• Wild animals when suspected of being infected with transmissible diseases
b. SRM (specified risk material)
c. Products of animal origin containing residues of environmental contaminants
d. All animal material collected when treating waste water from category 1 processing plants
e. Catering waste from means of transport operating internationally
f. Mixtures of category 1 material with either category 2 or category 3 material or both, including any material destined for processing in a category 1 processing plant
Category II matrial
a. Animals and parts of animals that died and not listed in category 1 by products, including
animals killed to eradicate an epizootic disease
b. Manure and digestive tract content
c. Materials collected from water from slaughterhouses d. Products of animal origin containing residues of drugs and other contaminants.
e. Mixture of Category 2 material with category 3 material
f. Animal byproducts other than category 1 material or category 3 material
Category III material:
a. Parts of slaughtered animals, fit for human consumption, but are not intended for human
consumption for commercial reasons.
b. Parts of slaughtered animals, which are rejected as unfit for human consumption but are not affected by any signs of disease communicable to humans or animals and derive from carcasses that are fit for human consumption.
c. Hides and skins, hooves and horns, pig bristles and feathers originating from animals that are slaughtered in a slaughterhouse, after undergoing ante-mortem inspection, and were fit, as a result of such inspection, for slaughter for human consumption.
d. Blood from slaughtered animals, except ruminants, that had Ante mortem inspection (fit for
human consumption)
e. By products from producing products for human consumption (including degraded bones and
greaves)
f. Former foodstuffs of animal origin or former foodstuffs containing products of animal origin,
other than catering waste, which are no longer intended for human consumption for commercial reasons or due to problems of manufacturing or packaging defects or other defects which do not present any risk to humans or animals.
g. Raw milk originating from animals that do not show clinical signs of any disease communicable through that product to humans or animals
h. Fish or other sea animals (except for mammals), caught in the open sea for the purpose of
fishmeal production
i. Fresh by products from fish from plants manufacturing fish products for human consumption
j. Shells, hatchery by products and cracked egg by products originating from animals which did
not show clinical signs of any disease communicable through that product to humans or animals
k. Blood, hides and skins, hooves, feathers, wool, horns, hair and fur originating from animals that did not show clinical signs of any disease communicable through that product to humans or
animals
l. Catering waste other than as referred to in category II wastes.
Principles of disposal and treatment of Category 1
Category 1
• Direct incineration in incineration plant or in co-incineration plant
▪ The gas products at the end of the burning process: ● Should be Homogenous
● Should Have 850oC temperature for at least 2 sec.
● The oxygen content of the gas should be at least 6%
• Processed in a processing plant into meat bone meals (MBM)
▪ Disposed as waste by incineration or
▪ Disposed as waste by burial in landfill
Principles of disposal and treatment of Category 2
Category 2
• Processed in a processing plant into meat bone meals which then will be:
▪ Disposed as waste by incineration or
▪ Disposed as waste by burial in landfill or
▪ Disposed as waste by composting or
▪ Disposed as waste by bio gas production
❖ MBM from categories 1 & 2 is forbidden to use in animal feeds.
Principles of disposal and treatment of Category 3 waste materials
Category 3
• Direct incineration in incineration plant or in co-incineration plant
• Processed in a processing plant
▪ Disposed as waste by incineration or
▪ Disposed as waste by composting
• Category 3 materials (a) to (j) can be processed into pet food dog chews and technical materials other than
fertilizers etc
Methods of ventiation:
- Natural: Windows, doors, gates, chimney trunk
- Mechanical
• Pressurised
• Extraction
• Even
• Recirculation
• Ventilation units
Evaluation of ventilation (one negative score for each)
- False ingoing air
- False outgoing air
- Recirculation from dung channel
- Whirl zones
- Exposure of drought/cold
- Air velocity >0.4m/sec close to animals
- Change of air velocity close to animals
- NH3 concentration of air velocity >10ppm
- Precipitation on construction elements
Characteristics of aerosols
• Non homogenous distribution
• Size: 10-4 – 102 μm
>20 μm → sedimentation within minutes
~10 μm → sedimentation: less than 25 minutes
<5 μm → slow sedimentation, over 1.5 hours
• Increasing humidity → agglomeration → increased sedimentation
Tolerable levels of aerial contaminant in animal confinements
- Total dust → 3mg/m3 (empirical)
- CO2 → 3000 ppm (limit value set by EU)
- NH4+ → 20 ppm (limit value set by EU)
- H2S → 0.5 ppm (limit value set by EU)
Methods of measuring aerosol particles
- Particle counting → Konimeter 10 particle counter
- Gravimetric methods
▪ Sedimentation: circular aluminiumfoil covered with film of Vaseline
▪ Persometer
3. Measurement of aerial germ count ▪ Microbial contamination of air → contamination infection → rate of survival depends on: ● Humidity of the air ● Frequent change of air temperature ● Bactericide irradiation ● Aerial oxygen content ● Open air factor
- Sedimentation
● Determines the number of Colony forming units that sediment onto the surface of culturing media in petri dish within given time of exposition - Slot sampler
● 20-33 mm long, hair thin slot beneath turntable petri dish with media
3. Andersen air sampler ● Utilizes the principle of the slot sampler by applying 6-8 stages ● Tiny holes of different diameters 4. Centrifugal air sampler ● Sampling drug and test strip
Gaseous contaminants:
- Ammonium
- CO2
- Hydrogen sulfide
- Carbon Monoxide
Measuring gaseous contaminants:
Instruments:
- Pump: manual or mechanical
- sampling device: impingers (capillary, cyclone)
or test tubes (with absorbants + indicators)
- Dräger sampler: CO2
- hydrazine absorbent and crystal violet redox indicator - Automatic air sampler: CO2
- Measures to measure ammonium:
- ▪ Indophenol colorimetric method
▪ Nessler reagent (Potassium tetraiodomercurate)
▪ Ammonium ion selective electrodes
▪ Dräger sampler: test tube contains bromphenol blue that binds the ammonium quantitatively
The degree to which ammonia forms the ammonium ion depends on…
the pH of the solution.
If the pH is low, the equilibrium shifts to the right: more ammonia molecules are converted into ammonium ions. If the pH is high (the concentration of hydronium ions is low), the equilibrium shifts to the left: the hydroxide ion abstracts a proton from the ammonium ion, generating ammonia.
Components of microclimate:
- Air quality → gas components, aerosols, air born germs
- Physical factors → dry/wet bulb temperatures, cooling power, mean radiant temperature, air velocity, thermal properties of floor
- Determine the heat sensation of animals - Others → light regime, noise, barometric pressure, etc.
Temperature:
- ways to easure it
● Mercury or ethanol thermometers ● Thermo elements ● Resistant thermometers ● Thermistors ● Simplest way of assessing the critical temperature → Six-type max-min thermometer
Instruments for short term measurements of microclimate:
▪ Temperature
▪ Relative humidity
▪ Estimation of the convective and radiant heat loss from animals
▪Estimation of the convective and radiant heat loss from animals
▪ Air velocity
Relative humidity is measured by:
● Hygrometers
● Psychrometer
Cooling power is measured by
the Hill-katathermometer
Instruments for long term measurements of microclimate:
▪ Thermographs
▪ Hygrographs
▪ Thermo-hygrographs
▪ Barographs
Data processing with regards to the microclimate:
- With regard to heat sensation and production
* With regard to the thermal properties of the stable
13.
- Name the most important energy therms regarding animals:
- Gross energy (GE) = faecal energy
- Digestible energy (DE) = urinary energy
- Metabolizable energy (ME)
- Non productive energy requirement → maintenance, locomotion, thermoregulation
- Productive energy (NE) → req. for fat deposition (50 kJ/g), req. for protein deposition
Factors that modify the gross energy intake
- Available feeding space
- Population density
- Defected feed
- Environmental temperature
- Factors that modify the digestibility of the feed
• Anti-nutritive substances
• Particle size of the feed
• Dry versus wet feed
• Cold environment enhances the intestinal motility → reduction of available time for digestion
▪ In sheep every OC ↓ below the lower critical temperature → ↓ digestibility by 0.1-0.2%
- Factors that modify the non productive energy requirement
- Factors that increase the genetically coded maintenance requirement
▪ Acclimatisation to cold
▪ Genetic selection (e.g. dwarf lines) - Factors that increase the locomotor activity
▪ High population density
▪ Oestrus - Factors that increase the thermoregulatory heat production
- Critical temperature of animals are affected by number of factors:
- Species, Breed, Age
- Single or group keeping, and size of the group
▪ Increased group size → lowered critical temperature - Plane of nutrition → Insulation of the skin
- Thermal properties of the floor → Concrete > Asphalt > dry straw bedding
- Air velocity
- Mean radiant temperature
- Define heat equilibrium:
Heat produced in the system vs. heat loss of the system
- Heat balance equation:
Heat balance: QA = LB+LV
• QA - animal heat production
• LB - Heat loss through construction
• LV - heat loss through ventilation
Optimal innside temp. should be reach heat balance
- Steps in developing heat equilibrium:
- Assess animal heat production
- Assess heat loss through stable construction
Depends on: Thermal transmittance, surface of a building element, difference inside/outside temp. - Assess heat loss through ventilation
- Methods of heating
- Room heating = Hot air blown inside through ducts.
Central heating. Floor heating. Heat exchanges - Local heating = Infrared bulbs. Infra gas heaters. Heating mats. Floor heating
- Heat balance of the animal organism
- Equation:
Q + (Rg+Cg) = (R + C1 + C2 + E)±S
• Left side of the equation → heat gain
▪ Q → heat production of the animal
▪ Rg → Heat gain by irradiation from the surrounding
▪ Cg → conductive heat gain
• Right side of the equation → heat loss ▪ R → heat loss by radiation
▪ C1 → conductive heat loss
▪ C2 → convective heat loss
▪ E → evaporative heat loss
▪ ±S → heat stored in, or lost from the animal in any given period
- Heat exchange between the organism and the environment
- Net radiant heat exchange
- heat gain by irradiation inn/outdoors - Heat exchange by convection
- Heat exchange by conduction
- Evaporative heat loss
- Heat gain by irradiation outdoor
● Solar energy reflected by the soil and vegetation
● Direct solar irradiation
● Diffuse irradiation (Electromagnetic waves are diffused by the aerial contaminants) X
● Long wave irradiation emitted by the soil and vegetation
● Atmospheric irradiation = energy absorbed by the vapour, CO2 and ozone content of the air
from the solar energy reflected back by long wave electromagnetic waves XX
- Heat gain by irradiation indoor
● Radiation reflected by walls and floors
● Long wave irradiation emitted by the walls and floor
● Diffuse irradiation (Electromagnetic waves are diffused by the aerial contaminants) X
● Atmospheric irradiation = energy absorbed by the vapour, CO2 and ozone content of the air
- Heat exchange by convection =
exchange of heat energy between the body surface and the energy content of the air molecules that form layer on the body surface
—> natural or forced heat exchange