Microbial control of postharvest diseases has been one

Microbial control of postharvest diseases has been one of the most extensively studied alternatives and appears to be a viable technology Control of microbial growth can be by inhibition of growth, killing the microorganisms or removing them from an environment. Antimicrobial agents can be divided into agents that kill microorganisms (bactericidal) and agents that inhibit growth (bacteriostatic) of the microbes. Electromagnetic irradiation is another effective way to sterilize or reduce microbial burden of almost any substance. Microwaves, ultraviolet (UV) radiation, X-rays, gamma rays and electrons are used although each type of irradiation has a specific mechanism.

Control of microbes is important in the food industry because some microbes spoil food or their growth in food produces toxins. The susceptibility of a product to food spoilage is a consequence of its suitability as a growth medium. Therefore, foods with low water activity are less susceptible to microbial spoilage.

Antibiotics Introduction Antibiotics are among the most frequently prescribed medications in modern medicine. Antibiotics cure disease by killing or injuring bacteria. The first antibiotic was penicillin, discovered accidentally from a mold culture. Today, over 100 different antibiotics are available to doctors to cure minor discomforts as well as life-threatening infections. Although antibiotics are useful in a wide variety of infections, it is important to realize that antibiotics only treat bacterial infections. Antibiotics are useless against viral infections (for example, the common cold) and fungal infections (such as ringworm). Your doctor can best determine if an antibiotic is right for your condition.

• Chemotherapy, or the use of chemical agents to destroy cancer cells, is a mainstay in the treatment of malignancies. The possible role in treating illness was discovered when the bone marrow suppressive effect of nitrogen mustard was noted in the early 1900's. Since that time, the search for drugs with anticancer activity has continued, and the goal of treatment with chemotherapy has evolved from relief of symptoms to cure. A major advantage of chemotherapy is its ability to treat widespread or metastatic cancer, whereas surgery and radiation therapies are limited to treating cancers that are confined to specific areas.

• Chemotherapy is the use of drugs that kill rapidly • • • dividing cells to treat cancer. Chemotherapy drugs are toxic to cancer cells, which take in the drugs as they multiply. Once inside the cells, the drug kills the cell or prevents it from dividing and forming new cells. Chemotherapy may consist of a single medication or a combination of drugs administered intravenously or orally. Most patients with active, symptomatic myeloma (stage II or III) are initially treated with some form of chemotherapy. There are several chemotherapy regimens that myeloma patients may receive, including: Conventional chemotherapy High-dose chemotherapy with stem cell transplantation Salvage therapy

• Almost all chemotherapy agents currently • available kill cancer cells by affecting DNA synthesis or function, a process that occurs through the cell cycle. Each drug varies in the way this occurs within the cell cycle. The major categories of chemotherapy agents are alkylating agents, antimetabolites, plant alkaloids, antitumor antibiotics, and steroid hormones. Each drug is categorized according to their effect on the cell cycle and cell chemistry.

• Alkylating agents kill cells by directly attacking DNA. Alkylating • • • agents may be used in the treatment of chronic leukemias, Hodgkin's disease, lymphomas, and certain carcinomas of the lung, breast, prostate and ovary. Cyclophosphamide is an example of a commonly used alkylating agent. Nitrosoureas act similarly to akylating agents and also inhibit changes necessary for DNA repair. These agents cross the bloodbrain barrier and are therefore used to treat brain tumors, lymphomas, multiple myeloma, and malignant melanoma. Carmustine (BCNU) and lomustine (CCNU) are the major drugs in this category. Antimetabolites are that drugs block cell growth by interfering with certain activities, usually DNA synthesis. Once ingested into the cell they halt normal development and reproduction. All drugs in this category affect the cell during the "S" phase of the cell cycle. Antimetabolites may be used in the treatment of acute and chronic leukemias, choriocarcinoma, and some tumors of the gastrointestinal tract, breast and ovary. . Examples of commonly used antimetabolites are 6 -mercaptopurine and 5 -fluorouracil (5 FU). Antitumor antibiotics are a diverse group of compounds. In general, they act by binding with DNA and preventing RNA synthesis. These agents are widely used in the treatment of a variety of cancers. The most commonly used drugs in this group are doxorubicin (Adriamycin), mitomycin-C, and bleomycin.

• An antiseptic is a substance which inhibits the growth and development of microorganisms. For practical purposes, antiseptics are routinely thought of as topical agents, for application to skin, mucous membranes, and inanimate objects, although a formal definition includes agents which are used internally, such as the urinary tract antiseptics.

• Antiseptics are a diverse class of drugs which are applied to skin surfaces or mucous membranes for their antiinfective effects. This may be either bacteriocidal or bacteriostatic. Their uses include cleansing of skin and wound surfaces after injury, preparation of skin surfaces prior to injections or surgical procedures, and routine disinfection of the oral cavity as part of a program of oral hygiene. Antiseptics are also used for disinfection of inanimate objects, including instruments and furniture surfaces.

• Disinfectants • are antimicrobial agents that are applied to non -living objects to destroy microorganisms, the process of which is known as disinfection. Disinfectants should generally be distinguished from antibiotics that destroy microorganisms within the body, and from antiseptics, which destroy microorganisms on living tissue. Sanitizers are substances that reduce the number of microorganisms to a safe level. The main difference between a sanitizer and a disinfectant is that at a specified use dilution, the disinfectant must have a higher kill capability for pathogenic bacteria compared to that of a sanitizer. Bacterial endospores are most resistant to disinfectants, however some viruses and bacteria also possess some tolerance.

• Types of disinfectants • Disinfection liquid attached to hospital bed • Alcohols, usually ethanol or isopropanol, are wiped over benches and skin and allowed to evaporate for quick disinfection. They have wide microbiocidal activity, are non corrosive, but can be a fire hazard. They also have limited residual activity due to evaporation, which results in brief contact times, and have a limited activity in the presence of organic material. Alcohol is not effective against fungal or bacterial spores. • Aldehydes, such as Glutaraldehyde, have a wide microbiocidal activity and are sporocidal and fungicidal. They are partly inactivated by organic matter and have slight residual activity. • Halogens • Chloramine is used in drinking water treatment instead of chlorine • • because it produces fewer disinfection byproducts. Chlorine is used to disinfect swimming pools, and is added in small quantities to drinking water to reduce waterborne diseases. Iodine is usually dissolved in an organic solvent or as Lugol's iodine solution. It is used in the poultry industry. It is added to the birds' drinking water. Although no longer recommended because it increases scar tissue formation and increases healing time, tincture of iodine has also been used as an antiseptic for skin cuts and scrapes.

Disinfection liquid attached to hospital bed

• Relative effectiveness of disinfectants One way to compare disinfectants is to compare how well they do against a known disinfectant and rate them accordingly. Phenol is the standard, and the corresponding rating system is called the "Phenol coefficient". The disinfectant to be tested is compared with phenol on a standard microbe (usually Salmonella typhi or Staphylococcus aureus). Disinfectants that are more effective than phenol have a coefficient > 1.

Examples of UV sensors for water disinfection monitoring

• Materials: • • • 8 nutrient agar plates 1 thumb forceps 1 bent glass rod 2 sterile 1 m. Lpipettes Alcohol for sterilization Metric ruler Antibiotic sensitivity disks Sterile paper disks Assorted antiseptics Ultraviolet lamps Nutrient both cultures of E. Coli and Bacillus cereus

• We have two methods: • 1 -Disk diffusion

• R=range • I = intermediate • S= senisivity Antibiotic Gentamycin R I S Less 15 16 -19 more 20

• 2 - Tube dilution • MIC (minimium inhibition con. )

http: //en. wikipedia. org/wiki/Disinfectant 1. http: //mic. sgmjournals. org/cgi/content/full/152/4/989 1. ^ EPA's Registered Sterilizers, Tuberculocides, and Antimicrobial Products Against HIV-1, and Hepatitis B and Hepatitis C Viruses. (Obtained January 4, 2006)