Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water— cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases' characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

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Water Microbiology. Bacterial Pathogens and Water

Membrane fouling control in ultrafiltration technology for drinking water production: A review

Disinfection of wastewater with peracetic acid: a review.

The photodegradation of pesticides is reviewed, with particular reference to the studies that describe the mechanisms of the processes involved, the nature of reactive intermediates and final products. Potential use of photochemical processes in advanced oxidation methods for water treatment is also discussed. Processes considered include direct photolysis leading to homolysis or heterolysis of the pesticide, photosensitized photodegradation by singlet oxygen and a variety of metal complexes, photolysis in heterogeneous media and degradation by reaction with intermediates generated by photolytic or radiolytic means.

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Reaction pathways and mechanisms of photodegradation of pesticides.

Disinfection is one of the most important processing steps affecting the quality and safety and the shelf-life of the end product in fresh-cut processing. Chlorine is the most widely used disinfectant in fresh-cut industry. However, recent outbreaks associated with pathogen contamination in fresh-cut vegetables raised the concerns about the efficacy of chlorine treatment in assuring the safety of the products. Moreover, due to the environmental and health risks posed by the use of chlorine, there is a trend in eliminating chlorine from the disinfection process. Thus, there is a need for alternative sanitizers to be used for the disinfection of fresh-cut vegetables, not only for the organic food sector but also for the conventional food processors. Another challenge for the food industry is the minimization of water consumption and wastewater discharge rates. The United Nations Environment Programme stated that Europe is one of the two global regions where more water is used for industry than for agriculture. Among the different industries, the food industry ranks third in water consumption and wastewater discharge rates coming after the chemical and refinery industries. The adoption of less water consuming systems is required for improved water management in the industry. Therefore the food industry is now seeking alternatives to chlorine which assure the safety of the products, maintain the quality and shelf-life, while also reducing the water consumption rates in processing. Chlorine dioxide, ozone, organic acids, peroxyacetic acid, electrolyzed oxidizing water and hydrogen peroxide are the main alternative sanitizing agents that gained interest in recent years. The effects of these disinfecting agents on the microbiological, nutritional and sensory quality of fresh-cut produce, and also the possible environmental impact and the potential on minimizing water consumption rates in the food industry are reviewed in this manuscript.

Potential alternative disinfection methods for organic fresh-cut industry for minimizing water consumption and environmental impact

The effect of coagulation with MF/UF membrane filtration for the removal of virus in drinking water

Bacteria which were beta-D-galactosidase and beta-D-glucuronidase positive or expressed only one of these enzymes were isolated from environmental water samples. The enzymatic activity of these bacteria was measured in 25-min assays by using the fluorogenic substrates 4-methylumbelliferyl-beta-D-galactoside and 4-methylumbelliferyl-beta-D-glucuronide. The enzyme activity, enzyme induction, and enzyme temperature characteristics of target and nontarget bacteria in assays aimed at detecting coliform bacteria and Escherichia coli were investigated. The potential interference of false-positive bacteria was evaluated. Several of the beta-D-galactosidase-positive nontarget bacteria but none of the beta-D-glucuronidase-positive nontarget bacteria contained unstable enzyme at 44.5 degrees C. The activity of target bacteria was highly inducible. Nontarget bacteria were induced much less or were not induced by the inducers used. The results revealed large variations in the enzyme levels of different beta-D-galactosidase- and beta-D-glucuronidase-positive bacteria. The induced and noninduced beta-D-glucuronidase activities of Bacillus spp. and Aerococcus viridans were approximately the same as the activities of induced E. coli. Except for some isolates identified as Aeromonas spp., all of the induced and noninduced beta-D-galactosidase-positive, noncoliform isolates exhibited at least 2 log units less mean beta-D-galactosidase activity than induced E. coli. The noncoliform bacteria must be present in correspondingly higher concentrations than those of target bacteria to interfere in the rapid assay for detection of coliform bacteria.

Enzyme Characteristics of β- d -Galactosidase- and β- d -Glucuronidase-Positive Bacteria and Their Interference in Rapid Methods for Detection of Waterborne Coliforms and Escherichia coli

Advanced wastewater disinfection technologies: Short and long term efficiency

Enzyme assays for 4-methylumbelliferyl-beta-D-galactopyranosidase and 4-methylumbelliferyl-beta-D-glucuronidase activities were used for rapid detection (25 min) of fecal water pollution and to determine the impact of sewage discharge in coastal waters. Two coastal areas were investigated: (i) an estuary characterized by a high degree of contamination downstream of a discharge from a sewage treatment plant and a low degree of water renewal and (ii) a fjord with a low degree of pollution and a high degree of water renewal. Statistical analysis showed that a global correlation curve could be used to estimate concentrations of culturable fecal coliform bacteria in the two coastal areas, although environmental factors important for cell physiology (e.g., salinity) varied at different sampling locations. The sensitivity limit for detection of 4-methylumbelliferyl-beta-D-glucuronidase activity corresponded to bacterial concentrations on the order of 10 to 100 CFU/100 ml. The 4-methylumbelliferyl-beta-D-galactopyranosidase assay was less sensitive because of a higher rate of substrate autohydrolysis. The detection limit corresponded to bacterial concentrations on the order of 100 to 1,000 fecal coliforms per 100 ml.

L Fiksdal

Papers

The effect of coagulation with MF/UF membrane filtration for the removal of virus in drinking water

Enzyme Characteristics of β- d -Galactosidase- and β- d -Glucuronidase-Positive Bacteria and Their Interference in Rapid Methods for Detection of Waterborne Coliforms and Escherichia coli

Advanced wastewater disinfection technologies: Short and long term efficiency

Monitoring of fecal pollution in coastal waters by use of rapid enzymatic techniques.

Application of rapid enzyme assay techniques for monitoring of microbial water quality.