Theoretical and Experimental Investigation of the Thermal Inactivation of Thermoanaerobacterium Thermosaccharolyticum and Geobacillus Stearothermophilus in Different Canned Food Matrices

In the canning industry, thermal preservation processes typically are designed based on Clostridium botulinum thermal destruction kinetics. However, some bacteria can still survive, necessitating implementation of stricter timetemperature regimen for sterilization process. The aim of this study was to compare processing effectiveness at F0 (sterilization value) 8 ±1 min from the perspective of the vegetable-based product canning facility, while analyzing the inactivation, viability, and recovery of thermophilic bacteria. Four commercial products [tomato soup and rassolnik soup - acidified food (AF), and mushroom soup and pea porridge - low-acid food (LACF)] with different heat transfer characteristics (convection and conduction) were inoculated with 6.6 log10 spores/ml Geobacillus stearothermophilus LMKK 244 (reported as DSM 6790 and ATCC 10149 in other collections) and 4.810 log spores/ml Thermoanaerobacterium thermosaccharolyticum DSM 571 spore suspensions. Food samples contaminated with bacterial spores were processed in a steam-air retort at 118 °C for 75 min. G. stearothermophilus and T. thermosaccharolyticum growth was not detected in AF samples (pH = 4.4 and 4.5), but was observed in LACF samples (pH = 5.1 and 5.8). Practical evaluation showed that T. thermosaccharolyticum did not survive thermal processing, which was verified using a presence/absence test after incubation at 55 °C. G. stearothermophilus did not survive thermal processing, but recovered in pea porridge (pH = 5.8) during incubation. Our observations showed that food pH is a crucial factor determining microorganism survival during heat treatment and may be used by the vegetable-based product canning facilities to improve the food sterilization conditions.

Design of Alginate-Based Bionanocomposites with Electrical Conductivity for Active Food Packaging

Bionanocomposite materials have been designed as a promising route to enhance biopolymer properties, especially for food packaging application. The present study reports the preparation of bionanocomposite films of alginate with different loadings of pure reduced graphene oxide (rGO) or of mixed zinc oxide-rGO (ZnO-rGO) fillers by solvent casting. Sepiolite is used to make compatible rGO with the hydrophilic matrix. The addition of fillers to alginate matrix maintains the low water solubility promoted by the calcium chloride treatment, and, additionally, they demonstrate a weaker mechanical properties, and a slight increase in water vapor permeability and wettability. Due to the properties of ZnO-rGO, the alginate bionanocomposites show an increase of electrical conductivity with the increase of filler content. While the highest electrical conductivity (0.1 S/m) is achieved by the in-plane measurement, it is in the through-plane measurement the remarkable enhancement of almost 30 times greater than the alginate film. With 50% of ZnO-rGO filler, the bionanocomposites present the highest antioxidant and antibacterial activities. The combination of electrical conductivity with bioactive properties makes these films promising not only to extend food shelf-life but also to allow packaged food sterilization at low temperature.

Gamma irradiation as suitable preservation method on herbal medicine: a review

The trend of consuming herbal medicines has been increasing over the past three decades. No less than 80% of the world's population has used herbal medicines as a treatment. One of the problems in herbal medicine is the high level of microbial contamination caused by raw materials and production processes. Various attempts have been made to overcome these problems, one of them is the gamma irradiation method. Although irradiation has been widely used for food sterilization, the use of irradiation for sterilization on herbal medicines is still debated. It is because irradiation may affect the composition of active compounds of herbal medicines. This review aimed to discuss the applications of gamma irradiation for herbal medicines by emphasizing the chemical constituent stabilities of herbal medicines.

MODERNIZATION OF INDUSTRIAL HORIZONTAL AUTOCLAVE

The article considers the problems of raising the efficiency of energy resources spent on the operation of a horizontal industrial autoclave, improving the quality of sterilized products and reducing the number of spoiled products. The analysis of the problems in automation control systems has been carried out and the shortcomings of the automatic control systems of technological process of canned food sterilization have been revealed. There has been described in detail the hierarchical structure of the autoclave control system. The main blockages caused by the pressure drop in air-main, water-main and steam-main are indicated. A detailed description of the cooling tower structure is given, the principle of cooling the circulating water and its supply to the consumer is analyzed. Within the framework of solving the problem of increasing the efficiency of energy resources and based on the technical characteristics, throughput and heat transfer coefficient, it is proposed to use a plate heat exchanger. There is described its operation principle, which includes heating the incoming water to a predetermined temperature and cooling it at the end of the sterilization cycle. The combined use of a cooling tower and a heat exchanger will help to greatly reduce the energy costs, because the water used in the sterilization process will not drain into the general sewer at the end of the process, but will be cooled in a cooling tower and supplied to cool the autoclaves. When heated, the live steam won’t go directly into the autoclave, but will be fed into a heat exchanger to heat the circulating water, which will significantly reduce the overheating of the sterilized product

Development of an Autoclave Thermal Processes Model for the Simulator of Canned Food Sterilization Process

The article describes an autoclave thermal processes model, which is used for the simulator of canned food sterilization process. The simulator is based on a simulation model that adequately describes the reaction of the autoclave to the actions of the control system and the operator of the sterilization unit. The model’s parameters were obtained by means of experimental data processing. The computer program ”autoclave Model” for simulating sterilization process in the steam and water environment is described. The examples of the canned food’s manual control sterilization modeling are shown. The results of numerical mathematical modeling of canned food sterilization processes in the autoclave showed a high degree of the implemented process models quality of approximation. The calculation schemes done as a result of the mathematical models creation were used to develop a hardwaresoftware complex of the sterilization process simulator. The increase of training level on carrying out process of canned goods sterilization will be provided as a result of designing the simulator of sterilization process in educational process. Consequently reducing defects in production and improving the quality of canned products are expected.