Microbiology BIOS 350 Ch 13.3

Nisin and natamycin

Inhibition of cell wall synthesis Preservation of dairy products, meats, and beverages

Surfactants

a group of chemical compounds that lower the surface tension of water. major ingredients in soaps and detergents

nitrites

added to processed meats to maintain color and stop the germination of Clostridium botulinum endospores.

Copper

algicide used to control algal growth in swimming pools and fish tanks.

Lysozyme

an enzyme found in saliva and sweat and tears that destroys the cell walls of certain bacteria

Silver

antiseptic preventing infection in burn Silver is often combined with antibiotics, making the antibiotics thousands of times more effective.

propionic acid

both inhibit enzymes and decrease intracellular pH a more effective preservative at a higher pH than either sorbic acid or benzoic acid.

Prionzyme

can remove prions on medical instruments

Supercritical carbon dioxide (scCO2),

certain sterilizing application nonreactive, nontoxic, and nonflammable properties 2 preserves the object's integrity and is commonly used for treating foods (including spices and juices) and medical devices such as endoscopes. It is also gaining popularity for disinfecting tissues such as skin, bones, tendons, and ligaments prior to transplantation. scCO2 can also be used for pest control because it can kill insect eggs and larvae within products.

Mercury

control microbial growth It was used for many centuries to treat syphilis. bacteriostatic

Alcohols

disinfectants and antiseptics ethyl alcohol (ethanol) and isopropyl alcohol (isopropanol, rubbing alcohol) not sporicidal dry quickly cause skin irritation

Bisbiguanides

disrupt cell membranes, causing cell contents to gel antiseptic not sporicidal. broad-spectrum activity against yeasts, gram-positive bacteria, and gram-negative bacteria,enveloped viruses. alexidine, is gaining popularity as a surgical scrub and an oral rinse because it acts faster than chlorhexidine.

benzoic acid

found naturally in many types of fruits and berries, spices, and fermented products. It is thought to work by decreasing intracellular pH, interfering with mechanisms such as oxidative phosphorylation and the uptake of molecules such as amino acids into cells. Foods preserved with benzoic acid or sodium benzoate include fruit juices, jams, ice creams, pastries, soft drinks, chewing gum, and pickles.

quaternary ammonium salts (quats)

group of cationic detergents, named for the characteristic quaternary nitrogen atom that confers a positive charge, that make up an important class of disinfectants and antiseptics stable, nontoxic, inexpensive, colorless, odorless, and tasteless. endospores are unaffected.

Peroxygens

hydrogen peroxide (damage to skin) peracetic acid (liquid or plasma sterilant) benzoyl peroxide(acne medication) ozone gas (sterilizing equipment) strong oxidizing agents that can be used as disinfectants or antiseptics.

sorbic acid

inhibiting various cellular enzymes, including those in the citric acid cycle, as well as catalases and peroxidases. It is added as a preservative in a wide variety of foods, including dairy, bread, fruit, and vegetable products.

Phenolics are classified as

intermediate to low level disinfectants -They inhibit microbial growth by denaturing proteins and disrupting membranes. -stable, persistent on surfaces, and less toxic than phenol. - bisphenol hexachlorophene: a disinfectant, is the active ingredient in pHisoHex, effective against gram-positive bacteria, including those causing staphylococcal and streptococcal skin infections. -triclosan: decades. Initially used in toothpastes, now commonly used in hand soaps, cutting boards, knives, shower curtains, clothing, and concrete, to make them antimicrobial. It is particularly effective against gram-positive bacteria on the skin, as well as certain gram-negative bacteria and yeasts. Bacteria can easily gain resistance to triclosan through a change to a single gene encoding the targeted enzyme in the bacterial fatty acid-synthesis pathway.

halogens

iodine, chlorine, and fluorine disinfection staining or skin irritation.

Heavy Metals

mercury, silver, copper, and zinc Bind to proteins and inhibit enzyme activity -Topical antisepticTreatment of wounds and burnsPrevention of eye infections in newborns Antibacterial in catheters and bandagesMouthwashAlgicide for pools and fish tanksContainers for long-term water storage

sulfur dioxide

prevents browning of foods and is used for the preservation of dried fruits; it has been used in winemaking since ancient times. Sulfur dioxide gas dissolves in water readily, forming sulfites. Although sulfites can be metabolized by the body, some people have sulfite allergies, including asthmatic reactions. Additionally, sulfites degrade thiamine, an important nutrient in some foods.

Alkylating agents

strong disinfecting chemicals that act by replacing a hydrogen atom within a molecule with an alkyl group (CnH2n+1), thereby inactivating enzymes and nucleic acids formaldehyde & formalin; Glutaraldehyde, o-phthalaldehyde (OPA), and ethylene oxide sterilization at low temperatures, preparation. Formaldehyde is very irritating to living tissues and is also carcinogenic; therefore, it is not used as an antiseptic. Ethylene oxide is a type of alkylating agent that is used for gaseous sterilization of heat sensitive items

Zinc

topical antiseptic creams such as calamine lotion, diaper ointments, baby powder, and dandruff shampoos.