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To a considerable extent, the dynamic growth in the production and use of polymer materials that has been observed for many years is related to their high resistance to the action of both abiotic and biotic agents. However, characteristics that are considered to be advantageous when viewed from the standpoint of production and use are perceived as faults, because once they have been used, these materials become a troublesome encumbrance for the environment; sooner or later a high proportion of them becomes waste and goes to the refuse tip or is dumped in the seas and oceans.

Infections by methicillin-resistant Staphylococcus aureus (MRSA) is gradually increasing in the community. There is a potential public health hazard resulting from S. aureus contamination of seafood, which is mainly due to unhygienic handling, processing, and storage environments. In Poland, the limits provided in European Commission Regulation 1441/2007 refer to the presence of Escherichia coli and S. aureus in shelled and shucked products of cooked crustaceans and molluscan shellfish. This study was designed to evaluate the occurrence of MRSA in samples of fish and seafood from commercial outlets located in the Tri-City area (Poland). In this study, we investigated a 44 food samples, including fish and seafood collected from various retail outlets in the Tri-City area of Poland. The first stage of staphylococcus isolation was initial culture in Giolitti-Cantoni broth. After 24 h, if blackening had occurred at the bottom (or there was general blackening of the medium), the samples were spread plated onto a CHROMagar MRSA base. The cultures were then incubated for 24 h at a temperature of 37°C. Of the 44 samples, 26 were positive for MRSA. The samples most often contaminated with MRSA were cephalopods (6 of 9) and crustaceans (10 of 15), followed by samples taken from mollusks (4 of 7) and fish (6 of 13). The correlation between the species from which the samples were obtained and the presence of S. aureus was not significant (P > 0.05). The high frequency of occurrence of MRSA in these products points to the potential risk of transmission of diseases through the food chain. The results obtained are significant and useful for S. aureus risk assessment programs for aquatic products. HIGHLIGHTS

The purpose of this paper has been to present the interactions between micro-organisms, food containers and packaged foods. The subject of assessment has been the impact of food packaging-related factors on properties of containers and the behaviour of food micro-organisms. In particular, one of the main questions concerns the role of food packages as a source of micro-organisms with the consequent food contamination. In addition, the influence of technological microflora on the packaging features should be discussed and analysed. In relation to these topics, the importance of microflora adhesion and the formation of biofilms on the inner surface of food packages are critical factors. The damage of packages and the possibility of mathematical modelling of micro-organism permeation dynamics through the leak have also been presented. Moreover, the impact of packaging systems and the chemical typology of food contact approved materials have been presented in the context of the preservation of micro-organisms inside containers.

Background. Methicillin-Resistant Staphylococcus aureus (MRSA), which is resistant to many antibiotics, creates a serious problem for human health if present in food. This study aimed to assess the quality of commercially-available fresh and frozen strawberries and to compare the behavior of staphylococci in these fruits as affected by the temperature of freezing. Material and methods. The research material included different species of fresh strawberries and strawberries frozen with the fluidization method to-40°C and packaged in an industrial environment. These were checked for the presence of Staphylococcus aureus resistant to methicillin (MRSA). The strawberries were purchased at food markets in the Tricity and were divided into two groups (A and B). Group A was analyzed without washing, group B was washed in sterile, distilled water for 15 minutes. The strawberries were placed in sterile PE/PA bags. Then 1 mL of Staphylococcus aureus Rosenbach ATCC 25923 and Staphylococcus epidermidis ATCC 12228 of known inoculum were added to each bag (except the control samples). The samples were mixed thoroughly and then hermetically sealed. The samples were then frozen and stored in the freezer at a temperature of-18 ±2°C for 2 months. In the material being tested Staphylococcus aureus was cultured in selective Baird-Parker RPF Agar. Incubation was carried out at a temperature of 37°C for 48 hours in sterile conditions. After 48 hours of incubation, characteristic colonies were transferred onto the reaction field of the PROLEX TM STAPH XTRA LATEX KIT. Results. The results obtained show that 1/3 of the samples of commercial strawberries analyzed were colonized by methicillin-resistant Staphylococcus aureus (MRSA). The process of fruit washing was observed to reduce the number of samples containing MRSA from 11.7 to 8.3%. There was no significant difference in the size of the S. aureus ATCC 25923 population after freezing the strawberries at-18°C, depending on the particular washing process for these fruits. The analysis of strawberries frozen with the fluidization method at-40°C showed a minimum contamination degree with S. aureus after the period of storage. Conclusions. Studies have shown that MRSA are present in 15.4% of strawberries obtained from the field. Storing strawberries frozen at-18ºC causes a reduction in the number of S. aureus by 0.16 log 10 CFU/g and S. epidermidis by 0.47 log 10 CFU/g when they were subjected to rinsing after harvesting. Effective inhibition of MRSA in strawberries is obtained when fluidization technology is applied at-40ºC.