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Prevention of Microbial Contamination during Manufacturing
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Chlorine can be used a sanitizer with sodium and calcium hypochlorite. Sodium and calcium hypochlorite ionize in water and produce Na+ or Ca+ ions and the hypochlorite ion OCL-, and an equilibrium is established with HOCL (74). Between a pH of 4.0 and 7.0, chlorine will exist predominantly as hypochlorous acid which is the active moiety of chlorine (75). Care must be taken to limit acidity as chlorine gas can be evolved if the pH falls too low. Chlorine is bactericidal, fungicidal and sporicidal (76,77). To use chlorine as a sanitizer, a concentration of greater than 100 ppm with a 30-minute contact will need to be ensured (78). The advantages of chlorine is that it has excellent antimicrobial activity, can be used in cold water and it is easy to verify the removal of its residues from equipment surfaces. The disadvantages of chlorine are that it has an odor, is less sensitive as a sanitizer as the pH increases and the hypochlorite ion predominates, sensitive to light exposure and temperature increases, its antimicrobial activity is inactivated by organics and it may react with metal surfaces by pitting stainless steel surfaces.
Battlefield Chemical Inhalation Injury
Published in Jacob Loke, Pathophysiology and Treatment of Inhalation Injuries, 2020
Synonyms for tabun (GA) include gelan, dimethylaminocyanophosphoric acid ethyl ester, ethyl dimethylamidocyanophosphate (MCE), dimethylamidoethoxy phosphoryl cyanide, ethyl phosphorodimethylamide cyanidate, ethyl-M-dimethylphosphoroamido cyanate, ethyl-M, N-dimethylphosphoramidocyanidate, Trilon 83, Substance 83, Le 100, and Taboon A. Its formula is CsHn^OjP; vapor density 5.6; specific gravity 1.08; boiling point 230-245°C (depending on purity). Pure Tabun is both colorless and odorless as a gas. Slight impurities in production may lend a faintly fruity aroma and brown color to the liquid. This odor does not constitute an adequate warning for the presence of toxic levels of the gas. The combustion and hydrolysis of Tabun causes the production of hydrogen cyanide. Calcium hypochlorite should not be used as a decontaminant because it leads to the production of cyanogen chloride.
Military Chemical Casualty Treatment
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
Timothy J. Byrne, Raymond Vazquez, Dan Boehm, Laukton Rimpel, Charles. G. Hurst
The chlorine solutions are placed in buckets for use in their particular area. The buckets should be distinctly marked, because it is very difficult to tell the difference between the 5% and 0.5% chlorine solutions. These solutions may be made using the 6 ounce calcium hypochlorite (HTH) containers that come with the Chemical Agent Decon Set. The 0.5% solution can be made by adding one 6 ounce container of calcium hypochlorite (CL) to 5 gallons of water. The 5% CL solution is made by adding eight 6 ounce containers of CL to 5 gallons of water. These solutions evaporate quickly at high temperatures, so if they are made in advance, they should be stored in closed containers.
Effectiveness of hydrogen peroxide treatments in preventing biofilm clogging in drip irrigation systems applying treated wastewater
Published in Biofouling, 2022
Nathan Japhet, Jorge Tarchitzky, Yona Chen
Farmers generally treat their DI systems by periodically applying highly concentrated chemicals and flushing the lateral lines. There are two main chemical treatments: (1) acidification to remove chemical fouling, specifically CaCO3 precipitation in Israeli DI systems; and (2) biocides such as sodium hypochlorite (NaOCl), calcium hypochlorite (Ca(ClO)2) and hydrogen peroxide (H2O2) (Katz et al. 2014). Chemical treatments for inactivating microorganisms are based on exposing the microorganisms to a disinfectant. Two of the most common disinfectants used are chlorine species and hydrogen peroxide. Chlorination prevents biofilm formation by killing bacteria and/or inhibiting bacterial reproduction and is the least expensive method for treating clogging due to biofouling (Li et al. 2010). Common sources for active chlorine include chlorine gas (Cl2(g)), sodium hypochlorite (NaOCl(l)), and calcium hypochlorite (Ca(ClO)2(s)) (Nakayama et al. 2007). This group has found, however, that treatment with NaOCl or HOCl could damage the diaphragm in the pressure-compensating emitter, leading to reduced emitter performance (Green et al. 2018).
A review on inactivation methods of Toxoplasma gondii in foods
Published in Pathogens and Global Health, 2018
Adel Mirza Alizadeh, Sahar Jazaeri, Bahar Shemshadi, Fataneh Hashempour-Baltork, Zahra Sarlak, Zahra Pilevar, Hedayat Hosseini
At present, two chemicals (chlorine and ozone) are most commonly used to treat food, especially drinking water, because their ability to inactivate T. gondii oocysts [123]. Both chlorine and ozone are strong oxidizing agents that can cause cell death through inhibition of enzymatic activity, damage to cells by modifying cellular components, alterations in cell permeability or damage to DNA and RNA [124]. A major advantage for the use of these chemical agents is that they are easier to handle than gaseous chlorine or calcium hypochlorite and require shorter contact times and dosages than chlorine for sodium hypochlorite and ozone, respectively. On the other hand, disinfectants are hazardous waste because they contain halogenated compounds, making it essential to use caution in their use in food to prevent cross-contamination. Principally, disinfectants or sanitizers can only function adequately for preventing cross-contamination of raw fruits and vegetables when the required disinfectant residual is controlled during washing by automated monitoring and dosing of the disinfectant [125].
Bio-efficacy of ultrasound exposure against immature stages of common house mosquitoes under laboratory conditions
Published in International Journal of Radiation Biology, 2020
Mohammad Sistanizadeh-Aghdam, Mohammad Reza Abai, Mansoureh Shayeghi, Amir Hossein Mahvi, Ahmad Raeisi
In recent years, there has been growing interest in the application of ultrasound technology as a novel and advanced oxidation process for water and sewage treatment (Mahvi 2009; Naseri et al. 2006), which was the main idea for conducting this investigation due to the presence of different types of portable ultrasound devices for water treatment on the market. Moreover, public opinion is calling for a reduction in the use of chemicals, e.g. calcium hypochlorite, for drinking water disinfection (Broekman et al. 2010), which was another reason for performing this research. In most subtropical areas, margination is accompanied by the lowest facilities for living, e.g. lack of piped drinking water and using tankers to sell up the water to householders and subsequent storing it in the cement open cisterns. Although, the water is disinfected in origin by chlorination, but it is quickly re-contaminated after being transported to houses due to the open status of cement tanks. In recent years, specific ultrasound devices have been commercially supplied for algae removal from ponds and lakes (Kotopoulis et al. 2009). However, further research is required into using portable dual-purpose ultrasound devices for controlling both algae and immature mosquitoes in the above and under-ground cisterns of drinking water at field conditions, e.g. in the southeast parts of Iran where different species of mosquitoes often choose ground cisterns as favorable habitats for development (personal observation). Moreover, the new ultrasonic technologies may also be used as a biocide to control the immature stages of mosquitoes that breed in the wastewater. Nonetheless, along with using ultrasound irradiation against immature mosquitos, its impact on non-target aquatic organisms should be also investigated (Bott and Tianqing 2004). This study was designed to find the effective regimens of ultrasound irradiation to reduce the density of mosquito immature in water under controlled conditions in the laboratory.