Evaluation of the efficiency of methods of cooling and freezing finished products for in-flight catering from a microbiological standpoints

Introduction. The quality and safety of on-board catering in the catering system being one of the most important areas of the state’s activities to ensure the health of flight personnel and air passengers is based on the identification of dangerous factors or conditions that cause them, during technological preparation, delivery of the finished product on board the aircraft and in flight conditions.

The purpose of study is studying the conditions for safe storage of ready-made on-board meals in epidemiological terms during production and in conditions of long air travel.

Materials and methods. Microbiological studies were carried out on 24 portion dishes of beef steak, chopped chicken schnitzel and pollock fish from batches of products prepared according to technical and technological maps in the on-board food workshop of AEROMAR JSC and intended as on-board food for air passengers. Cooling of the products after heat treatment was carried out to +4°C and –18°C using the following methods: immediately after the preparation of the products; products that have previously passed the cooling stage under natural conditions at an air temperature of +20°C and a speed of 1–2 m/s for 1 to 3 hours. Food samples were prepared in accordance with GOST 26669–85. Determination of mesophilic aerobic and facultatively anaerobic microorganisms (QMAFAnM), E. coli bacteria (coliforms), E. coli, S. aureus, sulfite-reducing clostridia, Enterococcus, Proteus, mold, yeast, pathogens, including salmonella and Listeria monocytogenes, were carried out by methods provided for by the current methodological documents.

Results. The duration of the cooling process up to +4°C after heat treatment of the product in a refrigerator at a temperature of +5°C was found to be directly dependent on the time of pre-cooling in air in natural conditions. The safety of fish and meat products in terms of microbiological indices, regardless of the method and time of cooling to +4°C, remained at the level of the regulatory requirements of TR CU 021/2011. An analysis of the absolute rate of the increase in the number of mesophilic and facultative anaerobic microorganisms showed that the process of reproduction of residual microflora and chopped chicken schnitzel and pollock fish under natural conditions proceeds more actively than in beef steak, which made it possible to limit the cooling time of products under natural conditions to 2 hours for subsequent portioning. Microbiological studies of frozen products after 90 days of storage at minus 18°C testified to its safety for nutrition and the possibility of use in long-term flight conditions while observing the cold regime on board the aircraft.

Limitations. In this article, we limited ourselves to studying the safety of methods of cooling and freezing products using a wide range of sanitary and microbiological indices, the state of product quality is a further stage of research.

Conclusion. The time of natural air cooling after heat treatment of meat and fish products should not exceed 2 hours, during which the products comply with the regulatory requirements of the TR CU 021/2011 and SP 2.3./2.4. 3590–20, The method of freezing products at –18°C in terms of microbiological indices is safe and can be recommended for feeding passengers under conditions of a long flight of an aircraft, subject to storage times.

Compliance with ethical standards. The study does not require the submission of a biomedical ethics committee opinion or other documents.

Contribution:
Trukhina G.M. – study design, analysis of the obtained data, preparation of the manuscript text, editing;
Borisova N.A. – study design, data acquisition, manuscript text preparation;
Mikailova O.M. – analysis of the obtained data, preparation of the manuscript text, editing of the manuscript text;
Drozd N.A. – data acquisition and analysis, manuscript text preparation.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Conflict of interest. The authors declare no conflict of interest.

Acknowledgement. The study had no sponsorship.

Received: November 8, 2024 / Accepted: December 3, 2024 / Published: December 28, 2024