The dairy farming industry has generally improved in terms of equipment and product performance, but innovation must be linked to traditional product specifications. During cheese ripening, the storage areas and the direct contact of the cheese with the wood must be carefully managed because the proliferation of contaminating microorganisms, parasites, and insects increases significantly and product quality quickly declines, notably from a sensory level. The use of ozone (as gas or as ozonated water) can be effective for sanitizing air, water, and surfaces in contact with food, and its use can also be extended to the treatment of waste and process water.
Area | Treatments | Target | Result | References |
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Ozone sanitization in working surface areas and equipment | Ozonated cold water (10 °C) for 15 min | Ozone treatment on stainless steel surfaces to remove milk residues | Chemical Oxygen Demand values are reduced by 84% | Guzel-Seydim et al., 2000 [88] |
10 min exposure with 0.5 ppm of ozonated deionized water | Effectiveness of ozone against microorganisms that can colonize metal surfaces | Microbial growth decreased by more than 4 log10 | Greene et al., 1993 [89] | |
Fresh 24-h bacterial cultures were exposed to ozone (0.6 ppm for 1 min and 10 min), chlorine (100 ppm for 2 min) or heat (77 ± 1 °C for 5 min) | Ozone, chlorine and heat applications were compared for killing effectiveness against food spoilage bacteria in synthetic broth | Ozone and chlorine significantly reduced the biofilm bacteria adhered to the metal coupons as compared to the control. No difference between ozone and chlorine inactivation of the bacteria. Ozone killed P. putida more effectively than chlorine | Dosti et al., 2005 [91] | |
20 min exposure with 0.4–0.5 ppm of ozonated water at 21–23 °C for 7 days |
Effect of ozone on more materials | Weight loss of all materials tested, but only weight loss for carbon steel was significantly | Greene et al., 1999 [47] | |
Ozone sanitization in working surface areas and equipment | Ozone concentrations from 1 to 10 ppm for 4 min |
Effect of gaseous-ozone and aqueous-ozone in commonly used devices of the dairy industry |
All surfaces were largely decontaminated after 4 min treatment | Megahed et al., 2018, 2019 [92,93] |
Ozone concentrations between 300 and 1500 ppm for 10–480 s | Effect of gaseous ozone and aqueous ozone in commonly used devices of the dairy industry |
Escherichia coli and Staphylococcus aureus died for 99.99% | Kowalski et al., 1998 [94] | |
Pseudomonas fluorescens, Staphylococcus aureus, and Listeria monocytogenes were treated with ozonized water (0.5 ppm) by immersion in static condition, ozonized water under flow conditions, and gaseous ozone at different concentrations (0.1–20 ppm) (20–60 min) | Inactivation of foodborne bacteria biofilms by aqueous and gaseous ozone | Aqueous ozone under static conditions resulted in an estimated viability reduction of 1.61–2.14 Log CFU cm−2 after 20 min, while reduction values were higher (3.26–5.23 Log CFU cm−2) for biofilms treated in dynamic conditions. With gaseous ozone, the highest concentrations estimated a complete inactivation | Marino et al., 2018 [52] | |
Ozone concentration of 5 ppm for 20 min | Effect of dissolved ozone on Pseudomonas biofilm on various surfaces | The biofilms growth on the different materials were inactivated | Shelobolina et al., 2018 [95] | |
Ozone sanitization in working surface areas and equipment | Ozone concentration of 1.0–1.7 mg L−1 followed by 0.8–1.1% of hydrogen peroxide | Antimicrobial effect of ozone water in combination with a hydrogen peroxide solution | Synergic treatments showed an antimicrobial effect against Pseudomonas fluorescens biofilm | Tachikawa et al., 2014 [96] |
Ozone concentration of 2 ppm for 15 min Monday to Friday and 120 min Saturday and Sunday | Reduce the environmental colonization of Listeria monocytogenes by means of an ozonation regime in all production areas | It showed a reduction in Listeria monocytogenes isolations from 15.0% in pre-zoning samples to 1.67% in post-ozonation samples in all areas | Eglezos and Dykes, 2018 [97] | |
Ozonated water with 16 mg L−1 of ozone for 20 min | Effect of acidic electrolyzed water, ozone water, or ultrasound on Staphylococcus aureus and Salmonella spp. biofilm on stainless steel surfaces |
Less than 0.8 Log CFU cm−2 of cells reduction in biofilm exposed to ozonized water |
Shao et al., 2020 [98] | |
Ozonated water with an ozone concentration of 1 ppm and 1–2% of malic acid for 20–40 min | The combined effect of malic acid and ozone as sanitizer to inhibit the biofilm formation by Salmonella typhimurium on different food contact surfaces |
Combination of malic acid with ozone reduced the biofilm formation on plastic bags, as well as on PVC pipes, suggesting it as an effective disinfectant for food contact surfaces | Singla et al., 2014 [99] | |
Ozone sanitization in working surface areas and equipment | Ozonated air had constant flow rate of 40 L min−1 and it generated 1.5 g h−1 of ozone (11–12 p.m. and 1–3 a.m. from Friday to Sunday). Hydrogen peroxide aerosolization was realized producing particles in the range of 5–15 μm at a concentration of 5–15% for 16–20 min. |
Effect of ozonation or chemical aerosolization through hydrogen peroxide to monitor the air microbial load in the dairy factory and in evaluating the air disinfection | Ozonation and hydrogen peroxide aerosolization were effective techniques in the inactivation of airborne microorganisms | Masotti et al., 2020 [100] |
Area | Treatments | Target | Result | References |
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Ozone milk treatment | Ozone concentration of 2.8 mg L−1 and 5.3 mg L−1 for 120 min | Ozone treatment to eliminate Cronobacter sakazaki from skimmed milk powder | Initial levels of Cronobacter were reduced by 2.71 and 3.28 log |
Torlak and Sert, 2013 [102] |
Pressurized ozone concentration of 5–35 mg L−1 for 5–25 min | Safeguard skim milk by diminishing its microbial masses | Pressurized ozone decrease the number of psychrotrophs by more than 99% |
Rojek et al., 1995 [103] | |
Controlled flow rate 0.5 m L−1 of oxygen (0.2 g h−1 of ozone) for 15 min | Gaseous ozonation treatment to reduce Listeria monocytogenes from both crude and marked milk tests | Gaseous ozonation totally wiped out Listeria monocytogenes from both crude and marked milk tests with a mean viable count of 5.5 and 5.7 log10 CFU mL−1, respectively. | Sheelamary and Muthukumar, 2011 [104] | |
Ozone gas at 1.5 mg L−1 for 15 min |
Ozone gas bubbling effects in the quality of raw milk |
Ozone decreases bacterial and contagious checks by up to 1 log10 cycle | Cavalcante et al., 2021 [101] | |
Gas ozone concentration of 75 mg L−1 for 10 min |
Decomposition of various antibiotic compounds in milk samples by ozonation process | Gas ozone caused a 95% reduction in antibiotics in milk samples | Alsager et al., 2018 [105] | |
Ozone milk treatment | Ozone concentrations of 2.16, 4.54, and 6.12 mg h−1 at selected volumes (1 L of each) and times of 2, 4, and 6 h |
Use of ozonation in a vortex reactor for removing antibiotics from milk | Post-ozonation of 400 mL of 5.52 μM various antibiotics for 20–40 min, their residue concentrations were 50.8–84.1 μg L−1 satisfying the relevant maximum residue limits | Liu et al., 2022 [106] |
In the first experiment, ozone concentrations were 35 and 45 mg L−1 for 0, 5, 15, and 25 min. In a second experiment, the water was ozonated at 45 mg L−1 for 15 min | Efficacy of ozonated water in controlling Escherichia coli O157:H7 | Reduction of 1.5 log cycles for 25 min in lactose-free homogenized skim milk. The refrigerated ozonated water put in storage for up to 24 h was effective to control E. coli | de Oliveira Souza et al., 2019 [107] | |
Gas ozone concentration of 80 mg min−1 for 5 min | Degradation of aflatoxins on milk samples | Aflatoxins were reduced by 50% | Ismail et al., 2018 [109] | |
Ozonation (9.99 mg min−1), UV light radiation (4.99 J cm−2) and pulsed electric field processes (13.15 µs) |
Synergistic effect of ozonation, UV and pulsed electric field processes on the decrease of aflatoxin in probiotic milk |
Reduction of levels of aflatoxins (total and M1). Lactobacillus acidophilus in the final product of 106 CFU g−1 | Khoori et al., 2020 [110] | |
Ozone milk treatment | 3.5 g ozone h−1 at 20 ± 2 °C for 60 min | Effect of ozone treatment against milk concentrate and whey concentrate, evaluating the physicochemical and textural properties and the effect on the microbial, antibiotic, and aflatoxin content | Ozone treatment reached 18.9% and 9.9% degradation of the aflatoxin M1 in milk concentrate and whey concentrate, respectively | Sert and Mercan, 2021 [111] |
Area | Treatments | Target | Result | References |
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Ozone in wastewater treatment | Ozone concentration of 30 mg dm−3 at 25 °C for 5 min | Reduce the content of organic pollutants in wastewater | Thanks to its microflocculation effect, the effectiveness of the following nanofiltration phase increases and, consequently, the reduction of COD is performed; in addition, there is a 40% increase in the biodegradability of nanofiltration residues | Làszlò et al., 2009 [117] |
Ozonation combined with hydrogen peroxide (30% w/w, [H2O2] = 9.007 mol L−1 and density of 1.1 g mL−1) and catalyzed by manganese (1.71 g L−1) in alkaline conditions (MnSO4.H2O, 98% of purity) | Degradation of organic matter in synthetic dairy wastewater | The optimal condition for the ozonation catalyzed by manganese at alkaline medium (C.O.D. removal of 69.4%) can be obtained in pH 10.2 and Mn2+ concentration of 1.71 g L−1, with COD removals above 60%. | dos Santos Pereira et al., 2018 [118] | |
Ozone in wastewater treatment | 20 min of reaction time with Mn-Fe-Ce/γ-Al2O3 catalyst, which has a dosage of 12.5 mg·L−1·min−1 of ozone. pH = 9, and the catalyst dosage was 15 g·L−1 | Mn-Fe-Ce/γ-Al2O3 for catalytic ozonation of dairy farm wastewater | The COD removal ratio of dairy farming wastewater can reach 48.9%. The BOD/COD increased from 0.21 to 0.54. Therefore, when the catalyst dosage increases (0–25 g L−1), the C.O.D. decreases | Li et al., 2020 [119] |
Five levels of ozonation flow rate (1, 2, 3, 4, 5 L min−1) were tested under the conditions that pH was 7.5 and reaction time was 60 min | Effect of ozone on undiluted dairy farm liquid digestate that contains high levels of organic matter, chromaticity and total ammonia nitrogen | After cascade pre-treatment, TAN, TN, COD, and chromaticity were reduced by 80.2%, 75.4%, 20.6%, and 75.8% respectively | Zhu et al., 2022 [120] | |
All pre-treatments were performed with ultrasound (US 200 W), ozone (4.2 mg O3 L−1) and US combined with ozone (US/ozone) for 10 min, 20 min, and 30 min, respectively | Dairy wastewater has been pre-treated with ultrasound, ozone and US combined with ozone to study the fate of enteric indicator bacteria and antibiotic resistance genes, and anaerobic digestion. | US/ozone pre-treatment was effective in the inactivation of enteric indicator bacteria. Total coliforms and enterococci were reduced by 99% and 92% after 30 min | Chen et al., 2021 [121] | |
Ozone in wastewater treatment | Continuous type O3 treatment system (43.26, 87.40, and 132.46 mg L−1) | Continuous type O3 treatment system to eliminate pathogens such as Salmonella Typhimurium and Escherichia coli O157: H7 in liquid dairy waste | Ozone reduced E. coli O157: H7 and S. typhimurium and the reductions increased with the exposure time, particularly at 87.40 or 132.46 mg·L−1 | Chang et al., 2022 [122] |
Area | Treatments | Target | Result | References |
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Use of ozone technology in cheese making processes and in storage/maturation condition | Ozone concentrations of 3–10 ppm for 30 days and of 0.2–0.3 ppm for 63 days | Effect of ozone in the ripening phase of Cheddar cheese | Higher ozone concentrations showed 6% more bacteriostatic action than lower concentrations | Gibson et al., 1960 [124] |
Cheese refrigeration at 2–4 °C, 85–90% RH with or without ozonation of the air in the room. Periodical treatments were done with concentrations of 2.5–3.5 ppm of gas ozone for 4 h at 2- to 3-day intervals | Application of ozone under refrigerated conditions on Russian and Swiss-type cheese to prevent mold growth | Ozone prevented mold growth for four months, while growth was observed on the control sample already after one month of storage. It prevented also mold growth on packaging materials for up to 4 months | Gabriel ’yants’ et al., 1980 [125] | |
4 ppm of gaseous ozone for 8 min at different stages of maturation | Efficacy of ozone against Listeria monocytogenes (artificially surface-inoculated up to 103 CFU g−1) | On Ricotta Salata below 10 CFU g−1 and, limited to the first days of maturation on Gorgonzola PDO and Taleggio PDO, the effect was a complete elimination | Morandi et al., 2009 [71] | |
Ozonated water (2 mg L−1 for 1–2 min) |
Ozonized water treatments for washing Minas Frescal cheese during storage | Reduction of the initial microbial load (by 2 log10 cycles) |
Cavalcante et al., 2013 [126] | |
Use of ozone technology in cheese making processes and in storage/maturation condition | Cheese preserved with a temperature of 5 ± 1 °C and a relative humidity of >80% for 3 months. It was used 8 g h−1 as the rate of ozone generation. | Efficacy of ozone treatment against molds present on the surface of cheeses and of the fungal spores that colonize the maturing rooms | Ozonation reduced the viable airborne mold load, but not on surfaces, resulting in a 10-fold reduction compared with the level observed for the control | Serra et al., 2003 [127] |
Gaseous ozone was produced of 40 g h−1 instead ozone water was done by coupling the same generator of ozone to a water bath (nominal volume of 100 L) | Explore the microbiota of the red–brown defect in smear-ripened cheese and how to prevent it | Ozone treatment guaranteed a complete elimination of yeast and bacteria, with no red–brown defect on the cheese rind | Guzzon et al., 2015 [128] | |
Use of ozone technology in cheese making processes and in storage/maturation condition | Ozone stream (2.5–3 ppm) for 0, 10, 30, and 60 s was used on the surface of freshly filled yogurt cups (240 g) before storage for the development of the curd (24 h). The brine solution bubbled with ozone was applied for the ripening of white (feta type, 400 g) cheese. Ozone gas was supplied for 0, 10, 20, and 30 min to the brine where cheese sample was then left for ripening (2 months) | Prevent contamination from spoilage airborne microorganisms | In ozonated yogurt samples, data showed a reduction in mold counts of about 0.6 Log CFU g−1 (25.1%) by the end of the monitoring period against the control samples. In white cheese matured with ozonated brine (1.3 mg L-1 O3, NaCl 5%) the treatment during two months decreased some of the mold load | Alexopoulos et al., 2017 [129] |
Cooling water (15 °C) with ozone (2 mg L−1) | Reduce the microbial spoilage load on Mozzarella cheese | Samples cooled in water pre-treated were characterized by low microbial counts, following 21 d of storage (by 3.58 and 6.09 log10 CFU g−1 lower total plate counts and Pseudomonas spp. counts, respectively, than in control samples) | Segat et al., 2013 [130] | |
Use of ozone technology in cheese making processes and in storage/maturation condition | The ozone application was conducted at 8 ± 2 °C and for the treatment, an ozone generator with a capacity of 3.5 g ozone h−1 was used for 5, 15, 30, and 60 min | Effect of ozone on butter samples | The results showed a higher microbiological quality in butter from raw cream with ozone treatment | Sert et al., 2020 [112] |
Concentrations of 2 and 4 ppm for 10 min were used against L. monocytogenes and resident microbiota of cheese rind samples stored at 4 °C for 63 days |
Effect of ozone on Listeria monocytogenes contamination and the resident microbiota on Gorgonzola cheese rind | In ozonized rinds, the final loads of L. monocytogenes were ~1 log CFU g−1 higher than controls | Panebianco et al., 2022 [131] | |
Use of ozone technology in cheese making processes and in storage/maturation condition | For the experiment at pilot plant scale the ripening was conducted in 8 m3 ripening rooms for 30 days with gaseous ozone at concentrations of 0, 2, and 6 mg m−3. For the experiment at dairy plant scale, a total of 30 cheeses with 15 days of ripening were subjected to maturation with gas ozone at concentrations of 2 mg m−3 for 45 days | Effect of gas ozone in soft cheese ripening, in particular its effect on the rind microorganisms | The results showed that gas ozone treatments had a significant fungistatic effect on cheese surface molds for pilot and industrial scale | Tabla and Roa, 2022 [132] |
Pecorino cheese samples were treated for 150 days overnight with gaseous ozone (200 and 300 ppb, 12 °C, and 85% R.H. for 8 h per day) | Effect of gas ozone on the mite pest control and on microbiological growth during Pecorino cheese ripening/storage | Starting from 25 days of storage, 200 ppb of ozone reduced mites and bacteria counts; molds and yeasts started from 75 days of storage. Ozone 300 ppb did not have the same positive impact on some aspects of overall quality. | Grasso et al., 2022 [134] |
This entry is adapted from the peer-reviewed paper 10.3390/foods12050987