Microbial Control of Growth Supplemental instruction Designed by Pyeongsug Kim ©2010 Fall 2010 For Dr. Wright’s Bio 7/27 Class Updated: 9/5/2015 3:05:49 PM Picture from

Designed by Pyeongsug Kim, © Kill the bacteria -eg. Disinfectant, sterilization… -Biocides : Kill the microbes: bacteria, funcgi, viruses Bactericidal Bacteriostatic -Prevent(inhibit) growth of the bacteria or reduce the microbes -but does not kill the bacteria  Removal or dilution of the antimicrobial can result in a resurgence of bacterial growth -eg. Handwashing with soap food in refrigerator Picture from

__________ - Bateriocides or germercides * Kill microbes -Disinfectants(Chemicals) -Toxic or non-toxic to skin -Objects or skin -Water treatment Facilities -Bacteria (including endospores), fungi, and viruses. -eg. Antiseptics (for skin) __________ - Bateriocides -Free of microbes -Bacteria (including endospores), fungi, and viruses. -Not for prion (protein) ! -Bio7/27 Lab. Hospital,… -eg. filtration, using heat (flaming loop), certain certain chemicals, or irradiation Disinfection Sterilization *Biocides – Kill microbes Biostatics – Prevent microbes Designed by Pyeongsug Kim, ©2010

Designed by Pyeongsug Kim, ©2009 __________ -Bacteriostatic -Chemicals (Disinfectants) -Non-toxic to skin -Surgery, handwashing - Bio7/27Lab. Hospitals,… Antiseptics __________ -Bateriocides or Bacteriostatics -Brief heat -Food or objects Pasteurization ry-clipart.jpg __________ - Bacteriostatics -Surface area including skin. Degerming

__________ -Biostatics -Objects -Health standards; clean in appearance *no specific level of control Sanitization __________ -Biostatics -ingredients or conditions(temp. pH, dry….) -Food or products -Delay spoilage - Jam, Pickling food, Dry food… Preservation Designed by Pyeongsug Kim, ©2009 __________ -Biostatics -heat, disinfectants, washing -safe to handle Decontamination Picture from

______________ -The use of specific methods to exclude contaminating microorganisms from an environment. - Microbiology laboratory, medical procedure….etc Designed by Pyeongsug Kim, ©2009 Aseptic technique

__________ -Resistant forms -Much harder to destroy than vegetative cells. -may destroy EXTREME heat or chemicals Designed by Pyeongsug Kim, ©2009 Endospores What types of organisms or other things are resistant to disinfectants? Endospores, Mycobacterium(waxy cell wall), Naked viruses, Protozoan cysts & oocysts, Pseudomonas __________ -Waxy cell walls -detected by acid fast stains -Resistant to chemicals -May be required strong toxic to destroy -TB Mycobacterium

__________ -Lack of a lipid envelop -More resistant to disinfectants than enveloped -Poliovirus. -However, viruses are NOT organisms or microbes. but, viruses are pathogens. Naked viruses _____________ - -can metabolize many chemicals - -Grow in disinfectants! - -Hospital-acquired infection (nosocomial) Pseudomonas *Prion are new concern in Hospital, but rare. Designed by Pyeongsug Kim, ©2009

_________ - the amount of timerequired to kill 90% of organisms. (Or 10% remained.) *Assumption: death occurs at a constant rate D-Value = 10 minutes 100,000,000 are present. 100,000, (10min)  10,000,000 10,000, (10min)  1,000,000 1,000, (10min)  100, , (10min)  10,000 10, (10min)  1,000 1, (10min)  (10min)  (10min)  1 Therefore, it takes 80 minutes (8D-values) to kill all. Designed by Pyeongsug Kim, ©2009 D value

How about… D-Value = 7 minutes 234,123,000 are present.  Looks complicated to you? But, very simple! Designed by Pyeongsug Kim, © ,123,000 cells are killed, in other word, 2 cells are remained. 234,123,000  One! 234,123,000  Two! 234,123,000  Three! 234,123,000  Four! 234,123,000  Five! 234,123,000  Six! 234,123,000  Seven! 234,123,000  Eight! Stop! 7 min.(D-value) X 8 = 56 minutes. Or 8D values Believe it or not… It is the answer.

Autoclaving Designed by Pyeongsug Kim, © high temperature, high pressure, steam (121 o C) (15 psi) -can kill endospores; may destroyprions -Chemical indicators Turn black  indicates if the objects are exposed heat. -Biological indicators Change color  growth of endospores.  Wrongfully work! -Bacteriocidal -surgical instruments, microbial media for culture Picture from

Designed by Pyeongsug Kim, © reduces numbers of microbes to tolerable levels (bacteriostatics) -HTST (High-temperature-short-time) method brief heat (72 o C ) -UHT (Ultra-high-temperature) method -Ice cream, Milk or juices, rubber, cloth,… -Anesthesia masks in hospitals Picture from

Designed by Pyeongsug Kim, © Commercial canning process -Industrial-sized autoclave - -designed to kill spore formers(C.botulinum) but, destroy almost all organisms. -12 D process (kill organisms) -Bacteriocidal Dry heat -flaming, baking, hot air oven -sterilize certain items -less effective than wet heat -oxidizes cell components; denature proteins. -Bacteriocidal -Glass Petri dishes and glass pipets powders, oils, and other anhydrous materials Picture from

Designed by Pyeongsug Kim, © disrupt tissue cell membrane, proteins, DNA -Disinfectants :chemicals kill microbes -antiseptics non-toxic to skin eg. Alcohol (weakly bacteriocidal) Picture from

Designed by Pyeongsug Kim, © Filtration Filtration  can sterilize but do not kill microbes. -membrane liquids (drinking water) -sterilizes heat-sensitive liquids (drinking water) - -HEPA (high-efficiency particular air) air filtration- filters remove particles. Hospitals -Laminar flow hoods :protect workers and materials from contamination. Laboratory

Designed by Pyeongsug Kim, © can be used foods. control E.coli (0157:H7), Salmonella in beef, poultry… - surgical supplies, drugs, Petri dishes - Not for skin - Bacteriocides - Endospores resistant to radiation Gamma radiationGamma radiation - penetrating - damage DNA and cell membrane UV radiationUV radiation - poor pemnetrating not effective for solid surfaces and turbid liquids - damage DNA - air, dringking water, surfaces… -Caution! in human tissue (skin and eyes)  skin cancers

Preservatives Designed by Pyeongsug Kim, © Food preservation -nontoxic for food Benzoic, sorbic -Benzoic, sorbic acids lower pH; bread, cheese, juice prevent growth  bacteriostatics by altering cell membrane function and energy transformation Nitrate -Nitrate spore formers inhibit spore formers  bacteriostatics prcessed meats, bacon, ham but, potential carcinogens -Preservation for non-food items sampoo, deodorants, soaps, mouth wash….

Designed by Pyeongsug Kim, © Cold storage -low-temperature; freezing -inhibit growth  bacteriostatic Psychrophiles -enzymatic inactive -Psychrophiles can grow  spoil the food in refrigerator Drying -draw water out of cells; dehydration -inhibit growth  bacteriostatic -Drying food Desiccation (removing water) Lyophilization (freeze-drying) ~ coffee, milk, meats, vegetables -Adding salt, sugar S.aureus can grow in high salt conditions meat jerkies