CC BY
19CONCLUSIONS
The most important factor affecting on the assessment of the reactive capacity of the soil bases of gravity-type quay walls and on the determination of work of the "structure- soil base" system is lateral soil pressure. Thus, the study of the reactive capacity of the soil base on the basis of the calculation model proposed of the "structure-soil base" system is an important task. The findings of studies can be used in the design and the construction of considered structures and so for the analysis of the technical condition of the operation structures including rigid retaining walls.
References
1. Khoneliia N.N., Dolinskaia N.B. The main directions of development of methods for calculating of the bearing capacity of the soil bases of port waterfront structures. Collection of Scientific Works. Building constructions. Kyiv: State Research Institute of Building Structures, 2014, no.2(75), pp. 404 - 411 [Published in Ukrainian].
2. Malyshev M.V., Savenkov A.S., Elizarov S.A. Development of areas of limit state in the soil base of a
square stamp. Bases, Foundations and Soil Mechanics. NIIOSP, 1991, pp. 15-17 [Published in Russian].
3. Iakovlev P.I. Results of experimental studies of the interaction of waterfront structures with soil. Collection of Scientific Works. Vladivostok, 1989, pp. 134 - 140 [Published in Russian].
4. Kushner S.G. Calculations of the bases of structures with using of limit stress state theory. Bases, Foundations and Soil Mechanics. NIIOSP, 2002, No. 1, pp. 2-8 [Published in Russian].
5. Zaretskii Yu. K. Bearing capacity of sandy bases of the foundations. Bases, Foundations and Soil Mechanics. NIIOSP, 2006, no. 3, pp. 2 - 8 [Published in Russian].
6. Khoneliia N.N. Lateral soil pressure on a retaining wall with a stone prism of improved shape. Collection of Scientific Works. Kyiv: State Research Institute of Building Structures, 2004, no. 61, pp. 219-225 [Published in Ukrainian].
7. Iakovlev P.I. Engineering calculation methods of the interaction of waterfront structures with soil on the basis of limit stress state theory. Training manual. Mortekhinformreklama, 1986, 50p. [Published in Russian].
OZONATION AS AN EFFECTIVE DISINFECTION METHOD FOR CHEESE RIPENING
CHAMBERS
Salodkaya K.,
Bachelor student, Grodno State University Trotskaya T.
PhD, Professor, Grodno State University
Abstract
A major advantage of ozonation over traditional thermal and chemical disinfection methods is that it is an effective, modern, and efficient means of dry, low-temperature ripening chamber treatment. The disinfecting effects of ozone on cheese ripening chambers ensure the necessary sanitary and hygienic conditions of air microflora.
Keywords: ozonation, disinfection of cheese ripening chambers, ozone in cheese technology, cheese storage, Penicillium, Cladosporium and Aspergillus molds in cheese production.
Ozonation is a modern and efficient method of dry low-temperature treatment for technological equipment, production premises and raw materials at food industry enterprises. Ozone is able to provide high-efficiency sanitary treatment and to destroy even those microorganisms that are resistant to chlorine, due to its strong disinfectant properties.
Ozone disinfection is simple and cost effective. The simplicity of the method lies in the fact that ozone is generated directly from the air, no additional reagents are required to obtain ozone. Ozone is synthesized from oxygen within a few seconds and quickly destroys microorganisms, 300-3000 times faster than disinfectants, ultraviolet lamps and chlorine-containing chemicals. [1]
Ozonation can be called one of the most cost-effective disinfection methods. For disinfection, only an ozonizer is needed, which will be used repeatedly in the
future. This technology does not require the use of water, consumes less electricity, results are quickly achieved, environment friendly method and does not require any special reagents or other means — all mentioned above shows the economic feasibility of using ozonation.
Ozonation is an eco-friendly disinfection method for both people and the environment, because decomposes into harmless oxygen and water within a short time. After airing, the rooms become absolutely clean and harmless to people. Chemical disinfectants, unlike ozone, do not destroy all bacteria and viruses, not all have sporicidal activity, and the reagent is also able to remain on the surface after treatment.
The dairy industry uses ozone for processing cheeses, specifically for sterilizing cheese ripening chambers. [2]
Cheese ripening is a crucial process for acquiring the distinct organoleptic properties of a particular variety. The treatment of cheese during maturation has a significant impact on its microbiological and biochemical changes, as well as its organoleptic characteristics. During this stage, the most important measures are to keep temperature, humidity, and air exchange conditions adequate and preventing the development of pathogenic microflora. As a part of the preparation process for cheese ripening, the premises must be carefully disinfected and maintained in a clean and hygienic state.
Cheese maturation is greatly influenced by the environment in which it is prepared. All cheese ripening rooms are humid and warm with no natural light, which makes it easier for mold to grow. The cheese chambers are ozonized before loading to protect them against mold growth.
Most of the mold in ripening chambers is of the genera Penicillium, Cladosporium, and Aspergillus, which together comprise 89.9% of all molds. The data showed the most commonly isolated Penicillium species and Aspergillus species were P. brevicompactum, P. aurantiogriseum, and A. versicolor. [3]
In ongoing studies, the cheese ripening rooms were ozonized, and the effectiveness of this treatment was assessed by sampling weekly throughout a 3-month period. The results obtained show that the ozone treatment disinfects the air form, but does not affect the viable form on the surfaces of the cheeses. It was only by wiping the surfaces with a commercial disinfectant that the viable load on the cheese surface was reduced. To improve the overall hygiene in the maturation room, a combination of cleaning modes - ozonation and chemical disinfection is recommended. [4]
Ozone has been used in cheese making in the United States since the 1940s. To prevent mold growth in the cheese ripening chamber, low ozone concentrations were used. Treatment with high and low ozone concentrations reduced the number of spores by 94% and 88%, respectively. As a result of the ozone treatment, no taste or odor defects were identified. [5]
Researchers have studied the preservation of Russian and Swiss cheeses using the refrigeration mode with air ozonation (2-4 ° C and 85-90% RH). A periodic treatment with ozone (2.5-3.5 ppm) for four hours every 2-3 days prevented the growth of mold on both types of cheese and packaging materials for at least four months without affecting the sensory properties or chemical composition of the cheeses. As another test, cheese that was matured at 10 ppm of ozone had an extended shelf life of 11 weeks. [6]
The microbiological parameters of Brazilian Minas Frescal cheese, which was treated with ozonated water (2 mg / l) for 1-2 minutes, were monitored throughout its storage in an ozonated water chamber. Ozonation reduced the initial values of total aerobic mesophils, lactic acid bacteria, yeast and their forms. Physicochemical properties of the cheese samples treated with ozone did not change. [7]
During the production of mozzarella cheese, ozone treatment was tested for its effectiveness for reducing bacterial contamination. In the laboratory, ozone failed to disinfect the surfaces of the cheese
(though it does disinfect the air microflora in the chamber perfectly):
Previously, the mozzarella samples were contaminated with 107 CFU / g Pseudomonas spp., the cheese was disinfected in 2 ways:
(1) Samples were immediately treated with ozonized water containing 2 mg / L ozone
(2) Samples were treated with ozonized water, 210 mg / L for 60 min, and then with gaseous ozone (1030 lg / L) for up to 2 h. [8]
Result — The cheese samples in (2) case are characterized by a lower number of microbes compared to untreated cheese. Thus, ozone treatment of tap water, used at various stages of mozzarella cheese making, improves the microbiological quality of the finished product, thereby increasing its shelf life.
Mold can grow well in the cheese ripening chambers because of their environment. If the camera is not properly disinfected, it may be contaminated with mold spores. Ozonation is an effective method for inactivating spores, both during cheese ripening and during storage (6). Ozone concentrations of approximately 0.05 ppm and 5 ppm in the air are inactivated by 80-90% and 99% of spores without negatively affecting the organoleptic properties of the cheese.
In 2003, the following experiment was carried out: the cheese ripening chamber was ozonized for 20 weeks, and the effectiveness of the procedure was monitored weekly — microbiological parameters were measured both in the air of the chamber and on the surfaces of the cheeses. Ozone gas has been proven to be very effective in reducing the total number of mold spores in the air, while it has not been possible to reduce the number of spores on the surface of cheeses. It has been concluded that gaseous ozonation may not eliminate the spores already present on the surface of the cheese entering the ripening chamber, but it may prevent the deposition of spores from the air during the ripening process. [9]
A study by Lanita and da Silva (2008) showed that 60 days of ozonation in a Parmesan-type ripening chamber reduced the amount of yeast and mold in the air by 63%.
A universal deodorizing and disinfecting agent, ozone has a powerful antimicrobial effect against a wide range of bacterial pathogens. It is also environmentally friendly, safe and the cheapest agent available.
As demonstrated above, ozone is a powerful disinfectant that can be used widely in cheese ripening chambers and is capable of preventing both food poisoning and bacterial infections. Managing the transition from conventional disinfectant production to ozone requires in-depth study, including determining the optimal ozone dose, contact time, and specific effects of ozonation on the maturity of cheese.
References
1. Nagy R. Application of ozone from sterilamp in control of mold, bacteria, and odors. Westinghouse Electric Corp., Bloomfield, NJ. Advances in Chemistry Series. 1957. pp. 57-65.
2. Nancy Awasti, Santosh Anand, The Role of Yeast and Molds in Dairy Industry: An Update, Dairy Processing: Advanced Research to Applications, 10.1007/978-981-15-2608-4, (243-262), (2020).
3. Freitas-Silva O and Venancio A (2010) Ozone applications to prevent and degrade mycotoxins: a review. Drug Metabolism Reviews 42 612- 620.
4. Gabriel'yants' M A, Teplova L N, Karpova T I, Kozlova R A and Makarova G F (1980) Storage of hard rennet cheeses in cold stores with ozonation of air (In Russian). Kholodil'naya Tekhnika 5 35- 37.
5. Shiler G G, Eliseeva N N, Volodin V I, Chebo-tarev L N and Matevosyan L S (1983) Method of ozonising rooms for ripening and storing cheeses (In Russian). Patent No. SU 1022688A.
6. Bullerman, L. B. 1981. Public health significance of molds and mycotoxins in fermented dairy products. J. Dairy Sci. 64:2439-2452
7. Gammon, R., and K. Kereluk. 1965. Gaseous sterilization of foods. AIChE Symp. Ser. 132:91-99.
8. Holah, J. T., S. J. Rogers, J. Holder, K. E. Hall, J. Taylor, and K. L. Brown. 1995. The evaluation of air disinfection systems. R&D Rep. Campden Chor-leywood Food Res. Assoc. 13:1-40.
9. Taniwaki, M. H., A. D. Hocking, J. I. Pitt, and G. H. Fleet. 2001. Growth of fungi and mycotoxin production on cheese under modified atmospheres. Int. J. Food Microbiol. 68:125-133.
