Modelling Microbial Load Reduction in Foods Due to Ozone Impact

African Journal of Food Science, 2021

Ozone is active against a broad spectrum of microorganisms. Ozone treatment can enhance safety and increase shelf life with limited impact on product quality. Ozone is known to be one of the strongest oxidizers that can have applications in foods. In the gaseous state, ozone is denser than air, colorless at lower concentrations and possesses a distinct odor. Ozone can be generated using a few methods, by photochemical procedures specifically UV light, electrolysis of water, with corona discharge being the most common method. In the food processing industry, ozone acts as a powerful sterilizer against both Gram-positive and Gram-negative bacteria, bacterial spores, fungi, viruses, and protozoa. Ozone affects the unsaturated lipids in the cell membrane causing leakage of cellular components that can lead to cell death. There are numerous examples to show that ozone has been successfully applied in food processing, specifically in sanitation by disinfecting food plant equipment and contact surfaces, packaging materials, water, air in storage and refrigeration systems, and for foods such as dried and fresh fruits and vegetables. The shelf life and quality of different food products can be maintained using ozone through reduction of spoilage microorganisms.

Journal of food protection, 2007

Each year in the United States, there are approximately 76 million foodborne illnesses, and fresh produce is the second most common vehicle for such illnesses. Before going to market, small fruits are not washed or treated in any manner to extend their shelf life. Washing alone is not a viable option, and the use of novel technologies should be investigated. One such technology is ozone treatment, which has been used with drinking water since the late 19th century. The efficacy of gaseous ozone for killing pathogens on strawberries and raspberries, which were used as a model for small fruits, was investigated in this study. Strawberries and raspberries were artificially contaminated with five strains of Escherichia coli O157:H7 and Salmonella enterica. Fruits were treated with four ozone treatments: (i) continuous ozone flow (5%, wt/wt) for 2, 4, 8, 16, 32, and 64 min; (ii) pressurized ozone (83 kPa) for 2, 4, 8, 16, 32, and 64 min; (iii) continuous ozone (64 min) followed by pressu...

Foods, 2021

Andean blackberries are highly perishable due to their susceptibility to water loss, softening, mechanical injuries, and postharvest diseases. In this study, the antimicrobial efficacy of gaseous ozone against spoilage (mesophiles, psychrotrophs, and yeasts and molds) and pathogenic (E. coli, S. enterica, and B. cinerea) microorganisms was evaluated during 10 days of storage at 6 ± 1 °C. Respiration rate and mass loss were also determined. Ozone was applied prior to storage at 0.4, 0.5, 0.6, and 0.7 ppm, for 3 min. The best results were observed with the higher ozone dose, with initial maximum reductions of ~0.5, 1.09, and 0.46 log units for E. coli, S. enterica, and B. cinerea, respectively. For the native microflora, maximum reductions of 1.85, 1.89, and 2.24 log units were achieved on day 1 for the mesophiles, psychrotrophs, and yeasts and molds, respectively, and this effect was maintained throughout storage. In addition, the lower respiration rate and mass loss of the blackberr...

Journal of food protection, 2003

A study was done to determine the efficacy of aqueous ozone treatment in killing Listeria monocytogenes on inoculated alfalfa seeds and sprouts. Reductions in populations of naturally occurring aerobic microorganisms on sprouts and changes in the sensory quality of sprouts were also determined. The treatment (10 or 20 min) of seeds in water (4 degrees C) containing an initial concentration of 21.8 +/- 0.1 microg/ml of ozone failed to cause a significant (P < or = 0.05) reduction in populations of L. monocytogenes. The continuous sparging of seeds with ozonated water (initial ozone concentration of 21.3 +/- 0.2 microg/ml) for 20 min significantly reduced the population by 1.48 log10 CFU/g. The treatment (2 min) of inoculated alfalfa sprouts with water containing 5.0 +/- 0.5, 9.0 +/- 0.5, or 23.2 +/- 1.6 microg/ml of ozone resulted in significant (P < or = 0.05) reductions of 0.78, 0.81, and 0.91 log10 CFU/g, respectively, compared to populations detected on sprouts treated with...

Journal of Food Agriculture and Environment

The following study focuses on the efficiency of ozone sanitation in the food industry with specific reference to fresh fruits and vegetables. Recent research findings including mechanisms of action, artificial synthesis, sanitation food efficiency and effects, application with different preservation techniques, as well as pros and cons have been reported. In particular, ozone reduces microbial spoilage and weight loss of apple.Onions treated with ozone showed that mould and bacterial counts were greatly reduced without any change in their chemical composition. Ozone treatments carried out on tomatoes did not affect their colour, sugar content, acidity and antioxidant capacity while it reduced the amount of aflatoxins when applied to peanuts. Red peppers, strawberries and cress treated with ozone showed a reduction in the microbiological population. In addition to many other examples it is also reported that the phenolic and flavonoid content of pineapples and bananas increased sign...

Food Microbiology

This research investigates the efficacy of gaseous ozone, applied under partial vacuum in a controlled reaction chamber, for the elimination of Salmonella inoculated on melon rind. The performance of high dose, short duration treatment with gaseous ozone, in this pilot system, on the microbial and sensory quality of fresh-cut cantaloupes was also evaluated. Gaseous ozone (10,000 ppm for 30 min under vacuum) reduced viable, recoverable Salmonella from inoculated physiologically mature non-ripe and ripe melons with a maximum reduction of 4.2 and 2.8 log CFU/rind-disk (12.6 cm(2)), respectively. The efficacy of ozone exposure was influenced by carrier matrix. Salmonella adhering to cantaloupe was more resistant to ozone treatment when suspended in skim-milk powder before aqueous inoculation to the rind. This indicated that organic matter interferes with the contact efficiency and resultant antimicrobial activity of gaseous ozone applied as a surface disinfectant. Conversely, in the abs...

International Journal of Food Science & Technology, 2008

Flaked red peppers inoculated with Escherichia coli, Bacillus cereus and B. cereus spores were exposed to gaseous ozone at 20°C and 70% relative humidity (RH). Ozone concentrations of 0.1, 0.5 and 1.0 ppm up to 360 min were used to reduce E. coli and B. cereus, whereas 1.0, 5.0, 7.0 and 9.0 ppm ozone concentrations for 360 min were used to treat B. cereus spores. When flaked red peppers were treated with 1.0 ppm ozone concentration for 360 min, B. cereus and E. coli counts were decreased by 1.5 and 2.0 log numbers, respectively. Bacillus cereus spores were reduced by 1.5 log numbers at ozone concentrations of 7.0 ppm or above for 360 min. There were slight changes in flavour, appearance and overall palatability of flaked red peppers treated with ozone between 5.0 and 9.0 ppm. Ozone concentration (1.0 ppm) for 360 min can be used to decrease E. coli and B. cereus, whereas ozone concentrations ‡5.0 ppm can be used to reduce B. cereus spores.

Food Control, 2009

Ozone is strong oxidant and potent disinfecting agent. There are numerous application areas of ozone in food industry such as sanitation of food plant equipments, surface hygiene and reuse of waste water. While the application of ozone for dried fruits disinfection and for fresh fruits and vegetables microflora destruction has been studied extensively, relatively little information is available on the potential of ozone to reduce microbial populations in date fruits. In this study, ozone was applied in gas form at three concentrations (1, 3, and 5 ppm) for four different periods (15, 30, 45 and 60 min) on Iranian date fruits and the reduction in the total bacterial count, Coliform, Staphylococcus aureus as well as yeast/mold counts were examined. The promising results indicated the efficacy of ozone to reduce the microbial populations in date fruits. Escherichia coli and S. aureus were not found on cultured plates inoculated with the treated samples after treatment with 5 ppm (p < 0.05) in 60 min. The method of ozone generation, type of application, as well as the optimal exposure time and concentration of ozone as an antimicrobial agent in date fruit is mentioned in detail.