Comparison of methods for enumeration of selected coliforms exposed to ozone

Adams, John C.; Lytle, M.S.; Dickman, D G; Foster, David H.; Connell, J. P.; Bressler, W R

doi:10.1128/aem.55.1.33-35.1989

Cited by 8 publications

(3 citation statements)

References 13 publications

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“…Rice et al (1987) achieved no significant difference in coliform recovery on m-T7 compared with m-Endo LES from mono-chlorinated samples. Adams et al (1989) found that the m-T7 medium performed no better than the medium in enumerating E. coli and C. freundii cells exposed to ozone. This method is much simpler than MPN, less labor intensive and requires less clean up of glassware.…”

Section: Membrane Filter (Mf) Methodsmentioning

confidence: 91%

Implication of coliforms as a major public health problem in Nigeria

Ishaku¹,

Ajumobi²,

Olayinka³

2014

J. Public Health Epidemiol.

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Water, the essence of life, is threatened by bacterial contamination. Coliform count is the major tool to determine the bacteriological quality of water. The determination is quite easy and informative. The different methodologies are employed depending on suitability by maximum probable number (MPN) which is the most accepted. The environment conditions like sunlight, water salinity, temperature etc. provide simple concepts to justify the coliform counts at various places. Faecal coliforms are discussed here with special emphasis as these which are very significant indicators of faecal contamination. Though uncomplicated, coliform counts also determine framing policies for safe and healthy living. However, caution has to be taken while interpreting the coliform data. This paper aims to present the best for understanding the coliform data and interpreting them in a justifiable way.

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Section: Membrane Filter (Mf) Methodsmentioning

confidence: 91%

Implication of coliforms as a major public health problem in Nigeria

Ishaku¹,

Ajumobi²,

Olayinka³

2014

J. Public Health Epidemiol.

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“…Moreover, microorganisms are inactivated by ozone at different rates, possibly because of differential membrane permeability ( O’Donnell et al, 2012 ). Several studies have reported that fecal coliforms showed considerably less sensitivity to ozone treatments, suggesting that they are more ozone-resistant than the other organisms ( Adams et al, 1989 ; da Silva et al, 1998 ). Prabakaran et al (2012) reported that E. coli revealed high sensitivity to ozone (0.1 mg/L for 15 min) compared to Klebsiella pneumoniae .…”

Section: Discussionmentioning

confidence: 99%

Improved Microbial Safety of Direct Ozone-Depurated Shellstock Eastern Oysters (Crassostrea virginica) by Superchilled Storage

et al. 2018

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The effect of superchilled storage at -1°C on the microbial safety of oyster depurated with 0.2, 0.4, and 0.6 mg/L ozone was studied for 14 days. Fecal coliforms (4,100–16,000 MPN/100 g), Escherichia coli (1,500–3,650 MPN/100 g), Vibrio cholerae non-O1/non-O139 (13.0–102.0 MPN/g), and Salmonella spp. (2.270–3.035 × 103 CFU/g) were initially present in raw oysters. After 6 h depuration, fecal coliform counts decreased (P < 0.05) to 300, 20 and 20 MPN/100 g for 0.2, 0.4, and 0.6 mg/L treatments, while a 0.3 log decrease in control oysters was observed. Initial E. coli counts decreased (P < 0.05) in oysters to 50, 20, and 20 MPN/100 g for 0.2, 0.4, and 0.6 mg/L treatments, respectively. A 1 log reduction in V. cholerae non-O1/non-139 levels were observed in 0.4 and 0.6 mg/L-treatments after 2 and 4 h depuration. Salmonella spp. was not detected in oyster samples after 6 h depuration in 0.4 and 0.6 mg/L-ozone treatments. Considering the bacterial loads after depuration, at the end of superchilled storage the 0.4 mg/L-ozonated oysters attained lower (P < 0.05) fecal coliform levels (280 MPN/100 g) and E. coli counts in 0.4 and 0.6 mg/L-ozonated oysters (20 and 95 MPN/100 g, respectively). A 2-log decrease in V. cholerae non-O1/non-O139 levels on day 5 in 0.4 and 0.6 mg/L-ozonated oysters (< 0.3 MPN/g) was attained. V. cholerae non-O1/non-O139 counts in control oysters decreased 1 log on day 9 of superchilled storage. Salmonella spp. was not detected in ozonated and superchilled stored oysters. Levels of fecal coliforms, E. coli, Salmonella spp., and V. cholerae non-O1/non-O139 in non-ozone depurated oyster samples were higher than in control, 0.4 and 0.6 mg/L ozonated oyster samples during superchilled storage. The cumulative mortality rates after 14 days of storage for superchilled oysters (22.2%) was higher (P < 0.05) than 0.6 mg/L O3 (7.2%) and 0.4 mg/L O3 (5.8%) treatments, and control oysters (5.6%). pH values in control oysters decreased significantly (P < 0.05) throughout the storage period but not in oysters of both ozone treatments, indicating no detrimental effects on oyster survival. The results of this study suggest that superchilled storage enables ozonated shellstock oysters (0.4 mg/L-6 h) stored for 9 days to be safe human consumption.

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“…Ozone concentration was colorimetrically measured using the diethyl-p-phenylenediamine (DPD) method [22] (ozone meter O3-1Z, Kasahara Chemical Instruments Corp., Saitama, Japan). DPD was used as the detection substrate, since it reacts with ozone and develops a color.…”

Section: Methodsmentioning

confidence: 99%

Effectiveness and safety of low-concentrated ozonized water for the reduction of contamination in dental unit water lines

Okubo

Ito

Shiota

et al. 2019

Heliyon

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Contamination of dental unit waterlines (DUWL) with heterotrophic bacteria can cause problems in immune compromised patients (aged, tumor and organ transplantation-patients). We focused on the use of low-concentrated ozonized water (OZW) as the biofilm formation restraint system for DUWL. Here, we examined the effects of low-concentrated OZW on the growth of bacteria and related biofilm formation and harmfulness to dental unit components (DUCs) in vitro . Objectives To evaluate the bactericidal effects of OZW on biofilms in DUWL and DUC in vitro . Methods Low-concentrated OZW (0.4 mg/L) was generated using an OZS-PTDX generator. Heterotrophic bacterial biofilms in old DUWL tubes and Candia albicans solution (control microbe) were treated with OZW for 1 h with gentle agitation before static culturing for 96 h in Reasoner's 2A liquid media. The control solutions were 0.1% cetylpyridinium chloride (CPC), chlorinated tap water (TW), and phosphate-buffered saline (PBS). Adenosine triphosphate (ATP) amounts of the microbes were measured and the biofilms of these microbes were observed using scanning electron microscopy (SEM). Moreover, surfaces of DUC soaked in OZW and TW were observed by SEM. Results The OZW reduced ATP levels in microbes to 50% compared to TW and PBS treatment, although CPC reduced it below detection limits. SEM observation revealed deformation of microbes cultured with OZW, whereas no changes were seen on DUC surfaces. Conclusions Low-concentrated OZW is bactericidal against heterotrophic bacteria biofilms and it is not harmful to DUC, suggesting that it might be useful in preventing DUWL contamination.

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Comparison of methods for enumeration of selected coliforms exposed to ozone

Cited by 8 publications

References 13 publications

Implication of coliforms as a major public health problem in Nigeria

Implication of coliforms as a major public health problem in Nigeria

Improved Microbial Safety of Direct Ozone-Depurated Shellstock Eastern Oysters (Crassostrea virginica) by Superchilled Storage

Effectiveness and safety of low-concentrated ozonized water for the reduction of contamination in dental unit water lines

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