Pengendalian Mikroorganisme Kuliah ke14 Mikrobiologi Cara Pengendalian n

Pengendalian Mikroorganisme Kuliah ke-14 Mikrobiologi

Cara Pengendalian n Mekanisme pengendalian dapat secara fisik atau kimia n Mungkin kombinasi keduanya n Metode Fisik n Panas lembab n Panas kering n Suhu rendah n Irradiasi n Filtrasi n Pemusnahan secara mekanis n Metode Kimia n Menggunakan berbagai jenis bahan kimia antimikroba. n Bahan kimia bergantung pada keadaan dan tingkat pengendalian yang diperlukan.

Cara Pengendalian n Prinsip pengendalian n Sterilisasi n Pemusnahan selluruh mikroorganisme § Barang yang steril harus benar-benar bebas dari mikroba, endospora dan virus Dapat dicapai melalui filtrasi, pemanasan, bahan kimia, dan irradiasi n Disinfeksi n Memusnahkan kebanyakan patogen n § Beberapa mikroba yang hidup masih ada Disinfektan = digunakan pada objek dan permukaan yang mati n Antiseptik = digunakan pada jaringan hidup n Pasteurisasi n Perlakuan panas secara singkat digunakan untuk mengurangi organisme yang menyebabkan busuknya makanan. n § Permukaan dapat dipasteurisasi.

Cara Pengendalian n Prinsip pengendalian n Dekontaminasi Perlakuan untuk mengurangi patogen sampai level aman. Degerming n Mekanisme yang digunakan untuk mengurangi jumlah mikroba pada suatu daerah. n n § Khususnya kulit n Sanitasi n Secara tidak langsung mengurangi populasi mikroba dalam jumlah besar. § Ini bukan cara pengendalian yang spesifik. n Preservasi n Proses yang digunakan untuk menunda kebusukan bahan yang tidak bertahan lama. § Sering penambahan-bahan penghambat pertumbuhan

Cara Pengendalian n Pertimbangan situasi n Metode pengendalian mikroba sangat bervariasi n Bergantung pada situasi dan tingkat pengendalian yang diperlukan § Kehidupan sehari-hari § Rumah sakit § Laboratorium microbiologi § Makanan dan fasilitas produksi makanan § Perlakuan air

Cara Pengendalian n Kehidupan sehari-hari n Mencuci dengan sabun dan deterjen mencapai pengendalian rutin. n n Hand washing single most important step to achieving control Sabun bertindak sebagai bahan pembasah. n Aids in mechanical removal of microorganisms § Memusnahkan sejumlah organisme dari lapisan kulit paling luar. § Mikroorganisme yang normal biasanya tidak berpengaruh karena menempati lapisan paling dalam.

Cara Pengendalian n Rumah sakit n Meminimalisasi populasi mikroba sangat penting. n Disebabkan bahaya infeksi nosocomial § Pasien lebih rentan terhadap infeksi § Patogen lebih sering ditemui pada pembangunan rumah sakit. § Berbagai organisme mengembangkan ketahanan antimikroba disebabkann konsentrasi antibitiok yang tinggi. n Peralatan harus disterilisasi untuk menghindari infeksi ke dalam jaringan yang lebih dalam.

Cara Pengendalian n Laboratorium Mikrobiologi n Menggunakan metode pengendalian yang akurat n Untuk memusnahkan kontaminasi mikroba terhadap sampel percobaan dan lingkungan § Teknik aseptik dan media steril digunakan untuk pertumbuhan § Menghilangkan organisme yang tidak diiinginkan § Bahan yang terkontaminasi diberi perlakuan untuk dibuang § Menghilangkan kontaminasi lingkungan

Cara Pengendalian n Makanan dan fasilitas makanan § Mempertahankan kualitas makanan; ditingkatkan melalui pencegahan pertumbuhan dan kontaminasi mikroba. n n Dicapai melalui pemusnahan organisme secara fisik dan kimia physical Perlakuan panas adalah mekanisme yang paling umum dan paling dpat dipercaya. Irradiation dibuktikan untuk memperlakukan beberapa makanan. Bahan kimia mencegah pembusukan. § Resiko keracunan

Cara Pengendalian n Fasilitas perlakuan air (water treatment) n Memastikan air minum aman n Chlorin biasanya digunakan untuk mendesinfeksi air. n Beberapa organisme tahan terhadap bahan kimia desinfektan.

Panas sebagai Pengendalian n Perlakuan panas sangat berguna untuk pengendalian mikroba n Relatif cepat, dapat dipercaya, aman, dan tidak mahal. n Panas dapat digunakan untuk sterilisasi dan desinfeksi. n Metode panas, yaitu: Panas lembab n Panas kering n

Panas sebagai Pengendalian n Panas lembab n Menghancurkan melalui koagulasi protein secara irreversible n Panas lembab, termasuk: n n n Pendidihan Pasteurisasi Tekanan uap

Panas sebagai Pengendalian n Pendidihan (100 °C) n Destroys most microorganisms and viruses n Not effective means of sterilization n Does not destroy endospores n Pasteurisasi n Pasteur developed to avoid spoilage of wine n Does not sterilize but significantly reduces organisms n Used to increase shelf life of food n Most protocols employ HTST method n Heated to 72°C and held for 15 seconds n Other protocol UHT n Heated to 140°C - 150°C, held for several seconds then rapidly cooled

Panas sebagai Pengendalian n Tekanan uap n Autoclave used to sterilize using pressurized steam n Heated water steam increased pressure n Preferred method of sterilization n Achieves sterilization at 121°C and 15 psi in 15 minutes n Effective against endospores n Flash autoclaving sterilizes at 135°C and 15 psi in 3 minutes n Prions destroyed at 132°C and 15 psi for 4. 5 hours

Panas sebagai Pengendalian n Panas kering n Not as effective as moist heat n Sterilization requires longer times and higher temperatures § 200°C for 1. 5 hours vs. 121°C for 15 minutes for moist n Incineration method of dry heat sterilization n Oxidizes cell to ashes Used to destroy medical waste and animal carcasses Flaming laboratory inoculation loop incinerates organism § Results in sterile loop

Metode Fisik lainnya n Heat sensitive materials require other methods of microbial control Filtration n Irradiation n High-pressure treatment n

Metode Fisik lainnya n Filtration n Membrane filtration used to remove microbes from fluids and air n Liquid filtration n Used for heat sensitive fluids n Membrane filters allow liquids to flow through § Traps microbes on filter n Depth filters trap microbes using electrical charge n Filtration of air n High efficiency particulate air (HEPA) filter remove nearly all microbes from air § Filter has 0. 3µm pores to trap organisms

Metode Fisik lainnya n Radiation n Electromagnetic radiation n Energy released from waves § Based on wavelength and frequency § Shorter wavelength, higher frequency = more energy n n Range of wavelength is electromagnetic spectrum Radiation can be ionizing or non-ionizing

Metode Fisik lainnya n Ionizing radiation n Radiation able to strip electrons from atoms n Three sources n n n Gamma radiation X-rays Electron accelerators Causes damage to DNA and potentially to plasma membrane n Used to sterilize heat resistant materials n n n Medical equipment, surgical supplies, medications Some endospores can be resistant

Metode Fisik lainnya n Ultraviolet radiation n Non-ionizing radiation n n Only type to destroy microbes directly Damages DNA § Causes thymine dimers Used to destroy microbes in air, drinking water and surfaces n Limitation n n Poor penetrating power § Thin films or coverings can limit effect

Metode Fisik lainnya n High pressure processing n Used in pasteurization of commercial foods n n Does not use high temperatures Employs high pressure § Up to 130, 000 psi n Destroys microbes by denaturing proteins and altering cell membrane permeability

Metode Kimia n Chemicals can be used to disinfect and sterilize n Called germicidal chemicals n Reacts with vital cell sites n n n Proteins DNA Cell membrane

Metode Kimia n Potency of chemicals n n Formulations generally contain more than one antimicrobial agent Regulated by n FDA § Antiseptics n n EPA n Sterilants = n Destroy all microorganisms n High-level disinfectants n n Destroys viruses and vegetative cells, Not endospores n Intermediate-level disinfectants § Disinfectants n Germicidal agents grouped according to potency n Kills vegetative cells fungi, most viruses, Not endospores n Low-level disinfectants n n Removes fungi, vegetative bacteria and enveloped viruses Not mycobacteria, naked viruses or endospores

Metode Kimia n Selecting appropriate chemical n Points to consider n Toxicity § Benefits must be weighed against risk of use n Activity in presence of organic material § Many germicides inactivated in presence of organic matter n Compatibility with material being treated § Liquids cannot be used on electrical equipment n Residue § Residues can be toxic or corrosive n n Cost and availability Storage and stability § Concentrated stock relieves some storage issues n Environmental risk § Is germicidal agent harmful to environment

Metode Kimia n Classes of chemicals n Germicides represent a number or chemical families n Alcohols n Aldehydes n Biguanides n Ethylene oxide n Halogens n Metals n Ozone n Peroxides n Phenolics n Quaternary ammonium compounds

Metode Kimia n Alcohols n Solutions of 60% - 80% isopropyl or ethyl alcohol kill vegetative bacteria and fungi n Not effective against endospores and some naked viruses n Mode of action n Coagulation of proteins and essential enzymes n Damage to lipid membranes n Commonly used as antiseptic and disinfectant n Limitations n Evaporates quickly limiting contact time n May damage material such as rubber and some plastics

Metode Kimia n Aldehydes n Destroy organisms by inactivating proteins and DNA n 2% glutaraldehyde solution most widely used liquid sterilant n n Orthophthalaldehyde studied as alternative Formalin used to kill bacteria and inactivate viruses n n Also used for specimen preservation Formalin is solution made from formaldehyde

Metode Kimia n Biguanides n Most effective member of group is chlorhexidine n n n Extensively used in antiseptics Relative low toxicity Destroys wide range of organisms

Metode Kimia n Ethylene oxide n Useful gaseous sterilant n n Destroys microbes including endospores and viruses Mode of action n Reacts with proteins Useful in sterilizing heat or moisture sensitive items n Limitations n n Mutagenic and potentially carcinogenic

Metode Kimia n Halogens n n Common disinfectants Mode of action n Oxidizing proteins and other cell components Includes chlorine and iodine Chlorine n n Destroys all types of organisms and viruses Used as disinfectant § Caustic to skin and mucous membranes n n Chlorine dioxide replacing chlorine in many applications Iodine n Kills vegetative cells § Not reliable with endospores n Used in tincture or iodophore on skin

Metode Kimia n Metal compounds n Compounds combine with enzymes and proteins n n Interfering with function High concentrations of many metals toxic to human tissue n Silver still used as disinfectant § Creams containing silver sulfadiazine used to prevent secondary infections § Also available on bandages for wound care

Chemicals as Control n Ozone n O 3 n Unstable form of oxygen Powerful oxidizing agent n Used as alternative to chlorine n n As disinfectant for drinking and waste water

Metode Kimia n Peroxygens n Includes hydrogen peroxide and peracetic acid n Powerful oxidizing agents n Readily biodegradable n Less toxic than ethylene oxide and glutaraldehyde

Metode Kimia n Hydrogen peroxide n Effectiveness depends on surface being treated n Living tissue produce catalase enzyme § Breaks down hydrogen peroxide to oxygen and water § More effective on inanimate object n n n Useful as disinfectant n Leaves no residue n Doesn’t damage most materials Hot solutions used in food industry Vapor-phase can be used as sterilant n Peracetic acid n More potent then hydrogen peroxide n Effective on organic material n Can be used on wide range of material

Metode Kimia n Phenolics n A. k. a carbolic acid n One of the earliest disinfectants n Now has limited use n Active ingredient in Lysol n Mode of action n Destroy plasma membrane n Denature proteins n Kills most vegetative cells n Can kill mycobacterium at high concentrations n Not reliable on all groups of viruses n Triclosan and hexachlorophene phenols used in soaps and lotions

Metode Kimia n Quaternary ammonium compounds n A. k. a Quats n Cationic detergents n Nontoxic n Used to disinfect food preparation surfaces n Mode of action n Reduces surface tension § Aids in removal of dirt and organic matter § Facilitates mechanical removal of organisms n Positive charge attracts Quats to negative charge of cell surface § Reacts with membrane § Destroys vegetative bacteria and enveloped viruses § Not effective on endospores, mycobacteria and naked viruses

Pengawetan Produk yang tidak tahan lama n Chemical preservatives n Some chemical preservatives are used in nonfood items n Food preservatives must be non-toxic to humans n n Benzoic acid, propionic acids, nitrate are commonly used Nitrate § Inhibits germination of C. botulinum endospores

Pengawetan Produk yang tidak tahan lama n Low temperature storage n Temperature dependent n n most microorganisms do not reproduce in ordinary refrigerator (0 -7ºC) Freezing n n ice crystals can cause irreversible damage to many microorganisms (kills up to 50% growth) Freezing stops all growth, but may start to reproduce again once food is thawed

Pengawetan Produk yang tidak tahan lama n Reducing water n Salt/sugar n Draw water out of cell n Less available for microorganisms n Drying n Desiccation n Salt cured meat Removing water such as milk powder

Pengawetan Produk yang tidak tahan lama n Lyophilization n Freeze drying n n Freeze food first followed by putting in vacuum

Metode Kimia Chemical Method Gas sterilants Ethylene oxide Antiseptics and disinfectants Germicidal chemical

Metode Kimia n Chemical preservatives n Numerous chemicals are used as preservatives n Formaldehyde, Quats, and phenols n Weak organic acids often used as food preservatives n Benzoic, ascorbic and propionic acids n Used in bread, cheese and juice n Mode of action § Alter cell membrane function § Interfere with energy transformation n Nitrates and nitrites used in processed meats n Inhibits germination of endospores and growth of vegetative cells n Have been shown to be potent carcinogen

Metode Kimia n Low temperature storage n Microbial growth is temperature dependent n Low temperatures slow down or stop enzymatic reactions of mesophiles and thermophiles § Some psychrophiles still able to grow n Freezing means of food preservation n n Essentially stops microbial growth Irreversibly damages cell § Kills up to 50% of microbes § Remaing cells still pose potential threat

Metode Kimia n Reducing water availability n Decreasing water availability accomplished by salting or drying food n Addition of salt increases environmental solutes § Causes cellular plasmolysis n Numerous bacteria can continue to grow in high salt environments § Staphylococcus aureus can survive in high salt concentrations n Desiccation or drying is often supplemented by other methods § Salting n Lyophilization (freeze drying) § Widely used to preserve foods like coffee, milk and meats