Extrinsic control parameters for ozone inactivation of<i>Escherichia coli</i>using a bubble column

Patil, Sonal; Cullen, Patrick J.; Kelly, Bridget; Frías, Jesús M.; Bourke, Paula

doi:10.1111/j.1365-2672.2009.04255.x

Cited by 24 publications

(19 citation statements)

References 24 publications

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“…Flow rate was previously determined to be a critical factor, at high flow rates a small number of large bubbles are produced, which rise to the liquid surface quickly, thereby escaping the medium quickly. The resulting poor gas dissolution reduces the contact time, leading to a lower inactivation rate (Patil et al, 2009). The antibacterial efficacy of ozone was greater when target microorganisms were suspended in pure water or simple buffers than in complex systems (Khadre, Yousef & Kim, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…Pure oxygen was supplied via an oxygen cylinder (Air Products Ltd., Dublin, Ireland) and the flow rate was controlled using an oxygen flow regulator. A previously determined optimum flow rate of 0.12L min -1 with an ozone concentration of 75-78µg mL -1 was applied for each treatment (Patil, Cullen, Kelly, Frias & Bourke, 2009). Ozone concentration was recorded using an ozone analyzer (built in ozone module OL80A/DLS, Ozone services, Burton, Canada).…”

Section: Ozone Treatmentmentioning

confidence: 99%

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Inactivation of Escherichia coli in orange juice using ozone

Patil¹,

Bourke²,

Frias³

et al. 2009

Innovative Food Science & Emerging Technologies

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112

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This research investigated the efficacy of gaseous ozone for the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in orange juice. Orange juice inoculated with E. coli (10 6 CFU mL -1 ) as a challenge microorganism was treated with ozone at 75-78µg mL -1 for different time periods (0-18 min). The efficacy of ozone for inactivation of both strains of E. coli was evaluated as a function of different juice types: model orange juice, fresh unfiltered juice, juice without pulp, and juice filtered through 500m or 1mm sieves. Fast inactivation rates for total reduction of E. coli were achieved in model orange juice (60 seconds) and in juice with low pulp content (6 min). However, in unfiltered juice inactivation was achieved after 15-18 min. This indicated that juice organic matter interferes with antibacterial activity of gaseous ozone. The effect of prior acid (pH 5.0) exposure of E. coli strains on the inactivation efficacy of ozone treatment was also investigated. There was a strain effect observed, where prior acid exposure resulted in higher inactivation times in some cases by comparison with the control cells.However, the overarching influence on inactivation efficacy of ozone was related to the pulp content. Generally, the applied gaseous ozone treatment of orange juice resulted in a population reduction of 5 log cycles.Key words: Escherichia coli, ozone, non-thermal inactivation, acid exposure, orange juice, microbial kinetics Industrial relevance: To facilitate the preservation of unstable nutrients many juice processors have investigated alternatives to thermal pasteurisation, including unpasteurised short shelf life juices with high retail value. This trend has continued within the European Union. However within the US recent regulations by the FDA have 3 required processors to achieve a 5-log reduction in the numbers of the most resistant pathogens in their finished products. Pathogenic E. coli may survive in acid environments such as fruit juices for long periods. This study demonstrates that the use of ozone as a non-thermal technology is effective for inactivation of E. coli and acid exposed E. coli in orange juice. Information on the design of the ozone treatment for inactivation of E. coli which results into safe juice products is also among the main outputs of this work. Ozone auto-decomposition makes this technology safe for fruit juice processing.4

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Section: Discussionmentioning

confidence: 99%

Section: Ozone Treatmentmentioning

confidence: 99%

Inactivation of Escherichia coli in orange juice using ozone

Patil¹,

Bourke²,

Frias³

et al. 2009

Innovative Food Science & Emerging Technologies

Self Cite

112

View full text Add to dashboard Cite

show abstract

“…Pure oxygen was supplied via an oxygen cylinder (Air Products Ltd., Dublin, Ireland) and the flow rate was controlled using an oxygen flow regulator. A previously determined optimum flow rate of 0.12 L/min with an ozone concentration of 0.098 mg/min/ml was applied for each treatment (Patil, Cullen, Kelly, Frias, & Bourke, 2009). Excess ozone was destroyed by an ozone destroyer unit.…”

Section: Ozone Treatmentmentioning

confidence: 99%

Ozone inactivation of acid stressed Listeria monocytogenes and Listeria innocua in orange juice using a bubble column

Patil¹,

Valdramidis²,

Cullen³

et al. 2010

Food Control

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“…At low flow rates, small bubbles are produced, however as the amount of ozone applied is low, inactivation is slow. Consequently, the inactivation of E. coli ATCC 25922 in the Tryptic Soy Broth (TSB) model system and treated in a bubble column was found to be dependent on gas flow rate (Patil et al, 2009b). After 25 minutes of processing, flow rates of 0.06, 0.12, 0.25 and 0.5 L/min provided complete microbial inactivation, whereas complete inactivation was not achieved with flow rates of 0.03 and 0.75 L/min after 30 minutes.…”

Section: Extrinsic Processing Parametersmentioning

confidence: 99%

Ozone Processing for Food Preservation: An Overview on Fruit Juice Treatments

Cullen¹,

Valdramidis²,

Tiwari

et al. 2010

Ozone: Science & Engineering

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This paper reviews the efficacy of ozone an emerging non-thermal food preservation technique for fruit juices and highlights changes in key microbial, quality and nutritional parameters. Ozonation of fruit juices has been identified as a potential technology to meet the United States Food and Drug Administration's requirement of a 5 log reduction in pertinent microorganisms found in juices. This review suggests that it is important to identify the critical extrinsic and intrinsic control parameters governing both the efficacy and quality effects during ozonation of fruit juices.

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Extrinsic control parameters for ozone inactivation ofEscherichia coliusing a bubble column

Cited by 24 publications

References 24 publications

Inactivation of Escherichia coli in orange juice using ozone

Inactivation of Escherichia coli in orange juice using ozone

Ozone inactivation of acid stressed Listeria monocytogenes and Listeria innocua in orange juice using a bubble column

Ozone Processing for Food Preservation: An Overview on Fruit Juice Treatments

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