Chapter 7 - Disinfection, Decontamination, and Sterilization (part 2) Flashcards

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The absence of of pathogenic microorganisms



substance that destroys/kills bacteria



substance that inhibits the growth and reproduction of bacteria



the number of microbes or amount of organic debris on an object at any given time



the presence of pathogenic materials



the contamination of a person or object by another



to reduce to an irreducible minimum the presence of pathogenic material



chemical agent that kills most microbes, but usually not spores; used on inanimate objects because compounds are too strong on living tissues

*is a category of disinfection


event-related sterility

determined by how a package is handled; package is considered sterile until opened or integrity of package material is damaged

*mostly used now, except implants still have expiration dates

*dust covers gave an extra 6 months on expiration



inanimate object that harbors microorganisms



agent that destroys fungus



invasion of the human body or tissue by pathogenic microorganisms that reproduce and multiply, causing disease



infection acquired within a health care facility - HAI



any microbe capable of causing disease


resident flora

microbes that normally reside BELOW the skin surface or WITHIN the body


transient flora

microbes that reside ON the skin surface and are EASILY REMOVED

*we try to lower their numbers for surgery to obtain surgically clean



infection, usually accompanied by fever, that results from the presence of pathogenic microorganisms



a resistant form of certain types of bacteria that are able to survive in adverse conditions



liquid substance that kills/destroys bacteria in the spore stage



having been rendered free of all living microorganisms, including spores


sterile field

specified area, usually the area immediately around the patient, that is considered free of microorganisms


sterile technique

techniques of creating a sterile field and performing within the sterile field to keep microbes at an irreducible minimum


strike-through contamination

contamination of a sterile field that occurs through the passage of fluid through, or a puncture in, a microbial barrier


surgically clean

mechanically cleaned and chemically disinfected but not sterile


terminal disinfection

to render item safe to handle by high-level disinfection

*not used invasively


terminal sterilization

to render items safe to handle by sterilization

*used invasively



living carrier that transmits disease

ex: mosquitos (west nile virus)



agent that destroys viruses


CDC and FDA classification system for patient care items and surgical devices





surgical instruments, devices that enter the vascular urinary systems, and any monitors or prove that enter deep tissue layers or cavities.

needles, catheters, implantable items (wires, screws, joint replacements, sutures)

Critical patient care items



process in which most but not all microorganisms located on animate surfaces, such as the skin, are destroyed


Semi-Critical patient care items

items that come into contact with mucous membranes or non-intact skin carry a lesser risk of infection

laryngoscopes, anesthesia and respiratory equipment, and some endoscopes. High-level disinfection should be used


Non-Critical patient care items

items that come into contact with a patient's intact skin. Least risk of infection

blood pressure cuffs, pulse oximeters, OR transport stretchers, and other furniture. Intermediate-level to low-level disinfection


AST recommended standards of practice applicable to decontamination and sterilization


for the Decontam. of Instruments

for Packaging Material and Preparing Items for Sterilization

for Monitoring Sterility


Disinfecting Agents

  • cleaning
  • disinfection
  • high-level disinfection
  • intermediate-level disinfection
  • low-level disinfection
  • Sterilization


Disinfecting agent: CLEANING

physical removal of blood, body fluids, gross debris (fat, tissue) (Bioburden)


Disinfection agent: DISINFECTION

destruction of pathogenic microorganisms by direct exposure to chemical or physical agents.

*Three levels of disinfection



kills all microorganisms except spores and prions (CJD)

*scope washers



kills most microorganisms, including bacteria, most viruses and fungi. M. Tuberculosis and HBV: ineffective against spores


Disinfection agent: LOW-LEVEL DISINFECTION

kills some fungi and viruses, and most bacteria, but is not effective against spores and M. tuberculosis


Disinfection agent: STERILIZATION

destruction of all microorganisms in or about an object with steam (flowing or pressurized) chemical agents (alcohol, phenol, heavy metals, or ethylene oxide gas) high-velocity electron bombardment, UV


disinfectant compounds also serve as sterilants when used in sterilization systems

Peracetic acid - used in Steris system

*liquids - items immersed to the liquid for certain amount of time


factors that influence efficiency of disinfectants

  • Concentration
  • Bioburden
  • Contact time
  • Physical factors of the solution, including temperature of the solution, water hardness and pH level and exposure time


Disinfectant concentration is too high

*increases the level of disinfection

*too corrosive for use on rubber


effectiveness of disinfection is decreased on contaminated items

*blood, body fluids, or tissue present on an item can make disinfectant difficult to be effective. - unable to contact surface

*must contact all surfaces

*thoroughly cleaned prior to decontamination process

*instruments disassembled, ratchets and locks opened


20-30 minutes

contact time that is generally recommended for high-level disinfection


10-15 minutes

contact time that is recommended for intermediate and low-level disinfection


safety with handling disinfectant solutions

  • review MSDS - kept accessible
  • PPE - strong chemicals can damage skin and tissue
  • stored in well-ventilated area
  • follow manufacturers directions for dilution of correct ratio
  • use for the purpose for which it was developed
  • do not mix solutions together - reaction could be flammable
  • dispose expired solutions


High-level disinfectant **can also be used as a sterilant


also known as Cidex

one of the best overall disinfectant/liquid sterilants on the market

used on devices that can withstand immersion in the liquid

used with decontamination or sterilization of rigid and flexible endoscopes


shelf life

Glutaraldehyde's is 14 days; with a surfactant it increases to 28 days and must be tested prior to each day during the 14-28 day period

the period of time between activation of the disinfection solution or number of uses after which the efficiency is diminished - must be at 2% strength - tested with test strips


requirements for items prior to being immersed in glutaraldehyde

  • cleaned and rinsed
  • not rinsed in close proximity to the soak basin of this product to prevent inadvertent dilution
  • all items should be dry to avoid dilution - even a small amount of water would dilute its effectiveness
  • the rinse water should be sterile - no tap water (this will prevent burning of tissue from the chemical


immersed 20 minutes at room temperature for high-level disinfection


immersed 10 hours for sterilization

Glutaraldehyde's exposure times


glutaraldehyde - alkylation of cell protein


dual purpose (disinfectant and sterilant)

noncorrosive to metals, lensed and cemented items, rubber and plastic

bactericidal against gram + and gram- microbes, tuberculocidal, virucidal


glutaraldehyde - alkylation of cell protein


noxious odor

irritating vapors

unstable shelf life

items must be cleaned and dried prior to immersion


Sodium Hypochlorite - household bleach - disrupts cellular metabolism

high-level disinfectant

effective fast-acting disinfectant solution for surfaces, floors, and equipment.

recommended by the CDC to clean blood and body fluid spills


Sodium Hypochlorite - high-level disinfectant


bactericidal, virucidal, tuberculocidal, effective against HIV, HBV, and other viruses


Sodium Hypochlorite - high-level disinfectant


Noxious odor


harmful to the skin

loses effectiveness in the presence of organic soil


Intermediate-level disinfectant compounds

capable of killing spores or certain hydrophilic viruses; however, they do kill all bacteria, fungi, and non-hydrophilic viruses.

used to disinfect countertops, OR furniture, floors, and other surfaces, and instruments that only come into contact with the skin of the patient


Phenol (Carbolic Acid) - denatures enzymes and causes cell lyses

intermediate-level disinfectant

used as a concentrate with detergent additives and is diluted with tap water. Used to disinfect large areas (floors and countertops) on a general basis.


Phenol (carbolic acid)


economical choice for the OR because it is a highly concentrated solution that is easily diluted

effective in eliminating fecal contamination


Phenol (carbolic acid)


Highly irritating to the skin - isopropyl alcohol should be used to neutralize

noxious odor

respiratory tract irritant

limited to disinfection of noncritical items


Quaternary Ammonium Compounds - cause leakage of the protoplasm in microbes

Intermediate-level disinfectant

they are commonly called quats, are bactericidal, fungicidal, and pseudomonacidal - unable to kill TB, spores, or viruses


Quaternary Ammonium Compounds


low cost

easy to mix




Quaternary Ammonium Compounds


kill limited number of classes of microbes

effectiveness easily reversed when solution contacts organic debris tap water, or detergents

gauze or fabrics absorb the disinfectant rendering it ineffective


Alcohol - causes protein denaturation, lysis, and metabolic interruption of cells

intermediate-level disinfectant

Isopropyl and ethyl alcohol in a dilution of 60-70% alcohol concentration are tuberculocidal, bactericidal, virucidal, and fungicidal; they are not sporicidal




nontoxic to the skin

effectively reduces number of bacteria on the skin - skin prep

good range of effectiveness against several types of microbes including HIV




slight odor

do not use to clean surgical instruments - highly corrosive

do not use to clean endoscopes - breaks down cement

highly flammable!


OSHA exposure control plan

explains the protective measures needed to create a safe working environment

A routine schedule should be established for the cleaning and decontamination of OR surfaces, scrub sinks, cabinets, floors, walls, and ceilings - Joint Commission will inspect


Decontamination practices in the OR : prior to the first procedure of the day

  • clean all surfaces in the OR
  • damp dusting should begin with the highest surface to lowest
  • when cleaning the OR table, pads removed hinges cleaned
  • OR table should be unlocked and moved to one side to facilitate mopping the floor under the table
  • clean blood and body fluids if present from the walls
  • clean cabinet doors
  • do not clean hot surgical lights - cool then clean


Decontamination practices in the OR : intraoperative

  • a basin with sterile water should be available in the sterile field for the soaking and cleaning of instruments. Never use saline, as the salt in the solution can cause pitting and corrosion of the metal. ***pitted instruments must be thrown away
  • instruments not easily cleaned with a sponge should be kept in the basin of sterile water to prevent the drying of blood, body fluids, and tissue on the instrument particularly if they will not be used again during the procedure.


Decontamination practices in the OR: between procedures

turnover - which marks the preparation for the next procedure

  • suction containers must be disconnected from the suction unit and wiped down
  • dispose sharps into puncture proof container
  • linen and trash bags must be sealed and placed in the designated area for transfer by environmental services personnel for proper disposal
  • instrumentation placed in case cart covered with plastic for transfer to decontam.


Terminal cleaning

end-of-day cleaning routine. A thorough cleaning of the rooms and areas outside of the OR after the last case of the day has been completed.

Zambonium - a machine to clean the OR floor.. floors are usually flooded, beds are broken down to power wash them


Other area of the surgical department that should be cleaned

substerile and storage rooms

stretchers for transporting

scrub sinks - due to their heavy use

hallway floors - cleaned similar to the OR floors

**scrub solution dispensers - gram negative bacilli have been known to contaminate disinfectant solutions and soap dispensers in the OR


Weekly cleaning in the OR

  • ceilings, walls, floors - including corridors
  • mounted lighting tracts
  • air vents/ heat duct grills
  • supply cabinets, shelves
  • sterile/nonsterile supply rooms
  • housekeeping supply room


Dirty Cases - last procedure of the day in an OR so a thorough terminal cleaning process will occur

floor should be cleaned with phenolic detergent

equipment and furniture - wiped with 70% alcohol


First step in the prevention of the transmission of microbes

Critical patient item or instrument that will be used on open tissue or be placed in the sterile field must be sterilized to remove all microbes, including spores

decontamination process


Decontamination room

a separate area, usually in proximity to the clean sterile processing area. The design of the decontamination area environment should follow these principles:

  1. filtered air is exhausted to the outside of the health care facility
  2. minimum air exchange rate is 10 times per hour
  3. temperature should be maintained between 64 -70 degrees with a humidity of 35% to 72%
  4. negative air pressure is maintained


The first step in the decontamination process begins

at the point of use

ST responsible for pre-soaking contaminated instruments to prevent drying of organic matter...

  1. sterile water; do not use saline
  2. enzymatic solution...a)proteolytic enzymatic cleaner; facilitates the removal of protein materials such as blood. b)Lipolytic enzymatic cleaner; facilitates the removal of fatty material such as adipose tissue and bone marrow
  3. detergent solutions


advantages of presoaking solutions

sterile water - keeps organic debris moist

enzyme - removes moistened and dried debris w/o the need for mechanical action

detergent - keeps organic debris moist while loosening dried-on debris


limitations of presoaking solutions

sterile water - ineffective in softening or removing dried debris

enzyme - efficiency depends on concentration of solution, temperature, and contact time

detergent - mechanical action is necessary to completely remove soil


when cleaning instruments, remove organic and inorganic soil through one of the following methods, depending on the type of cleaning solution used







process of binding minerals in the solution. this prevents their deposit on the surface of surgical instruments, which causes spotting



catalysts that aid in breaking down organic soil such as blood and tissue into solution



action o dispersing two liquids not capable of being mixed



action by which the solubility of a substance is increased within a solution


common chemical cleaners:


organic substance that aids in the chemical reaction of breaking down organic debris.

specific to type of debris to be removed

more effective in warm water


common chemical cleaners:


specifically for use in ultrasonic cleaners.

may contain a surfactant (to enhance wetting ability) and chelating agents


common chemical cleaners

Manual detergent

products usually used for hand cleaning of items and/or presoaking. Some of the manual cleaners are high foaming and therefore should not be used in mechanical cleaning equipment.

mechanical action is required to assist in removing the soil. Surgical instruments must be thoroughly rinsed after being placed in the detergent


common chemical cleaners


liquid solution that is available in three different pH levels.

Neutral-ph= least corrosive/less effective

Moderate-ph= low-level alkaline, may be combined w/surfactants and chelating agents. Safe on SS instruments but harmful to the chromium oxide layer that protects instruments from corrosion

High-pH= most effective/corrosive, must be neutralized


cleaning - the first step in decontamination

ideally this trio arrangement is utilized

First sink: wash sink with water and detergent

Second sink: intermediate rinse with distilled water

Third sink: final rinse with distilled water


Manual cleaning of instruments is a three-step process

---instruments are immersed in a solution of lukewarm water, detergent, and/or enzymatic cleaner with a neutral pH. Avoid hot water to avoid blood and tissue from being set on surface

---The last step is to rinse the instruments in distilled water

---To avoid spotting the instruments, the items should be immediately dried after rinsing


Mechanical cleaning... recommendations for preparing instruments for the washer-sterilizer, washer-decontaminator, or ultrasonic washer

---instruments must be placed into a perforated or wire mesh tray

---heavier instruments should be placed on bottom, delicate on top

---hinged instrument must be left in an open position to allow water, cleaning agent, and steam to contact the total surface area

---instruments with attachments must be dissembled

---instruments with concave surfaces should be placed upside down to allow proper cleaning, rinsing, steam contact, and drainage



*does not incorporate a sterilizing phase

*4 cycles - prerinse, cleaning, final rinse 180-195 degrees, and drying phase



*gross soil is removed then processed in here

*SS instruments not placed next to other metals-reaction could damage instruments

*low-sudsing only - high-sudsing will leave a residue

*8 cycles - presinse, automatic detergent injection fill phase, wash phase, postrinse, sterilization phase, lubrication (milking), drying phase


Ultrasonic Cleaner

Used to remove small organic particles and soil from areas of instrumentation that manual or mechanical cleaning cannot reach. ex: box locks, serrations, and ratchets

Utilizes cavitation for cleaning insruments



  • uses high-frequency sound waves
  • ultrasonic waves travel thorough the cleaning agent, causing a rapid motion of molecules
  • bubbles enlarge, become unstable, and implode creating a vacuum dislodging minute particles of soil
  • not considered a disinfecting process but rather a cleaning


Instrument preparation

here in the "clean room" (CSPD) is where instruments are checked for function and integrity and prepared for sterilization


Advantages to non-woven materials

Impervious to moisture = waterproof


types of pouch packaging used by health institutions

Paper-plastic combinations that are used for steam and EtO sterilization

Tyvek-plastic combination used for EtO (only) and Sterrad


Reusable rigid instrument containers with locking lids have become popular with health care facilities. The containers are multipurpose and have the following characteristics:

  • provide containment during sterilization
  • provide assurance of pkg. integrity
  • easily opened/excellent presentation of contents
  • used for returning contaminated items to decontam.
  • disposable chemical indicator to verify exposure may be incorporated within the lid
  • available in a variety of sizes/locking lid/sturdy construction



recommends that instrument sets should not exceed 25#


Preparation of instruments include:

  1. inspection
  2. reassembly
  3. preparation

*One of the steps is proper inspection of powered instruments

*An instrument may need to be lubricated and operated for a designated amount of time to ensure lubricant distribution. The power hose should be checked for cracks and cuts. The power hose should be coiled loosely to prevent kinking and damage.


Preparation of instruments for effective sterilization..If done properly will ensure:

  • the sterilant comes into contact with all surface areas
  • instruments are positioned in a protective manner until used
  • instruments are evenly distributed


How should instruments be placed:

A mesh-bottom or wire mesh basket with an absorbent towel lining the bottom


instruments that need special preparation prior to sterilization

instruments with lumens, such as a Frazier suction tip, may have air trapped in the lumen and may prevent steam from contacting the inner surface. To prevent this entrapment of air, a residual amount of distilled water should be left inside the lumen.


more special preparations of instruments prior to sterilization

basin sets are conducive to the formation and retention of condensate due to their density. Basins that will be nested within each other or that may contain other metal items must have adequate air space between each item. An absorbent towel should be used to separate the basins and items. It should be fully opened to absorb the condensate, to aid in air removal, and to create an adequate space for the penetration of steam. A towel should also be used to separate items from each other in the basin.


Julian date

indicates the date of sterilization. It is the number of the calendar day 1-365/366


Steam Sterilization

the destruction of all microorganisms in or about an object can be accomplished with the use of steam under pressure.

dependable and inexpensive method


Methods of sterilization

Chemical agents (alcohol, phenol, heavy metals, and ethylene oxide gas,) high-velocity electron bombardment, or UV radiation.


How are microbes killed

  1. moisture
  2. heat

*heat alone is sufficient, but the process is accelerated with the addition of moisture and pressure. Pressure that is greater than that of the atmosphere is necessary to increases the temperature of the steam in order to cause the destruction of microbes.


Factors that are critical to the outcome of the sterilization process

  1. time
  2. contact: sterilant must have contact with all surfaces of the items being sterilized
  3. temperature
  4. moisture
  5. pressure: increases the temperature of steam to the level where it can destroy all microbes


sterilization failures

Containers are posiitoned incorrectly on the cart. Instrument trays, basins, and peel packs must be positioned to allow air to escape

wrapped packs are placed too close together on cart. Packs should be loosely arranged on the autoclave cart to allow complete removal of trapped air and free circulation of steam


components of an autoclave

some generate their own steam, but others rely on an outside source. When this happens the walls of the chamber are preheated before the steam is allowed into the chamber. This is accomplished with a metal jacket that is built around the chamber. The space between the jacket and chamber is filled with steam to preheat the chamber walls when the machine is turned on.


Gravity displacement sterilizer

rely on gravity to passively remove air from the sterilization chamber. Steam enters at the top of the chamber and displaces the air. Air is heavier than steam, so as the steam occupies more space, the air is pushed out the drain at the bottom front of the chamber. The pressure in the chamber increases the temp. of the steam reaches a preset temperature.

these are slower than prevacuum/dynamic-air removal sterilizers because gravity is relied on to remove the air.


Bowie-Dick test

named after two English microbiologists

J.H.... ad J....

This test is used in the prevacuum sterilizer to check for air removal and entrapment and is conducted daily on the first run of the day before any loads are sterilized or after it has undergone repair


Immediate use or "flash" sterilization

unwrapped items, such as instruments that have been dropped during a procedure.

*can be performed in a gravity or prevacuum sterilizer


advantages of steam sterilization

saturated steam is many times more effective in transferring thermal energy than hot air

most economical and inexpensive



dynamic-air removal (prevacuum) steam sterilization cycle times

instrument set wrapped

270 degrees for 4 minutes


gravity displacement steam sterilization

instrument set wrapped

270 degrees for 15 min.


methods of monitoring the sterilization process

  1. mechanical
  2. chemical - indicators
  3. biological - Bowie-Dick


chemical indicators

consists of paper that has been impregnated with a dye that changes color in the presence of temperature and sterilant


Internal steam chemical indicators

placed inside packages, peel pack, and instrument trays to indicate the contents have ben exposed to the conditions of sterilization.

available as commercial strips of paper impregnated with ink

should be placed in the area of the package or tray where the greatest challenge exists for penetration of steam an air removal.

It is read when the package or tray is opened at time of use


Biological indicator (BI)

*a device that contains a specific type of microorganism that is killed when exposed to the sterilization conditions

*contains the spore "Geobacillus stearothermophilus"

*incubated for 24hours before the reading is recorded


where is the (BI) test pack placed

area of the sterilizer that is most difficult for the sterilant to reach. The "coldest" area where air entrapment is most likely to occur. This is the bottom front of the sterilizer cart over the chamber drain.


EtO Ethylene Oxide

gas sterilant used to process materials that cannot be processed using steam sterilization, such as heat or moisture sensitive materials.


EtO factors for proper sterilization

humidity: moisture hydrates spores and bacteria that would otherwise be resistant to the gas alone. Humidity is kept between 30-80%


Moving EtO loads

loads from this sterilizer must be pulled instead of pushed to avoid the possibility of "downwind" of the fumes

*EPA concerned personnel safety with its use. It's CFCs damaging to the ozone layer

*OSHA developed strict PEL with its use


Advantages of EtO

used for heat sensitive materials

less corrosive to metals

less damaging to plastic and rubber


Disadvantages of EtO

aeration times an be lengthy - up to 21 days with pacemakers

personnel hazards


(BI) for EtO

Bacillus atrophaeus


(BI) for Hydrogen Peroxide gas plasma

Bacillus atrophaeus


(BI) for Peracetic acid

Geobacillus steraothermophilus


Hydrogen Peroxide gas plasma limitations

difficulty with narrow-lumen or channeled instruments of sterilant reaching the innermost surfaces


HPGP (hydrogen peroxide gas plasma) packaging

must be made of nonwoven polypropylene or other synthetic, non-cellulose, nonwoven material. Peel packages made of Tyvek are appropriate for use.


Peracetic acid

skin tumors in mice

used with Steris maching 122degrees

used for rigid and flexible endoscopes

used for single sterilization cycle ***FOR IMMEDIATE USE ONLY"

cannot be stored!

impregnated strip "wash-off"

chemical strips detect that the active ingredient is present in greater than 1500 parts per million are available for routine monitoring of concentration levels


ionizing radiation

used by industrial manufactures to sterilize prepackaged products for use in the OR and hospital environment. Uses a process of irradiation to produce thermal and chemical energy, killing microbes/spores. Gamma Rays or Beta particles to sterilize

Manufacture does not use chemical indicators...pkg. integrity is the method for determining sterility


Event-Related sterility

replaced older time-related system. It is determined by how it is handled and that contamination is not by expiration.

economical for healthcare facility. It eliminates pulling expired items from shelves.


Principles are synonymous with



Principles and practices/actions of sterile technique

designed to protest the sterile field from contamination and keep microbial counts to an irreducible minimum


Surgical conscience

basis for the practice of strict adherence to sterile technique by all surgical team members. It involves a level of honesty and moral integrity that every surgical technologist must uphold in order to deliver quality patient care

"There can be no compromise of sterile technique"

safety of patient depends on strict adherence to this practice. And other members of the surgical team.

Adherence to asepsis aids in preventing SSIs

understanding of microbiology, disease transmission, cross-contamination, disinfection and sterilization


Primary method through which microbes are kept to a minimum in the OR

Sterile field

A separate sterile area that consists of the surgical site itself, draped portions of the patient, OR table, sterile portions of the gown and gloves, draped ring stands, Mayo stand, and back table. Sterile instruments, sutures, an equipment to be used during the procedure


Inside of the paper wrappers containing linens or other sterile items is considered sterile except...

1 inch perimeter around the outside edge of the wrapper


The integrity of sterile packaging must be checked before opening

No evidence of strike-through, tears, or punctures, all seals must be intact; and CIs must have turned color to indicate exposure to sterilizing conditions


The surgical gown is considered sterile in front 2 inches below the neckline to table level; bilaterally; and sterile gloved hands to 2 inches above elbows

upper chest area on the front of the gown is considered nonsterile because it cannot be directly viewed by the wearer and because of the possibility of the chin coming into contact with this part of the gown


Sterile surgical team members should either pass while facing one another or pass back to back by rotating 360 degrees

The ST should turn her or his back to a nonsterile individual or area when walking past


A nonsterile individual must maintain a minimum distance of 12in. from any sterile item, area, or field to prevent contamination

additionally, equipment and furniture that is not covered by a sterile drape must not be included in the sterile field and must be kept a minimum of 12 in. away from a sterile surface pr item. The ST must be conscious of these nonsterile items and personnel and maintain the 12 in. distance


When draping a nonsterile table to create sterile field the nonsterile individual should cuff the hands in the underside folds of the drape or table cover to avoid contaminating the top surface

drape should be opened away from the body toward the far side of the table and then toward the body to avoid contamination