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Maintaining precise temperature control is vital for cold chain food transport, as temperature fluctuations can cause significant food safety and quality issues. During transport, ice that melts can promote the growth of microbes and their spread, resulting in microbial cross-contamination. This study developed sustainable, non-melting, self-sanitizing "ice cubes" using food grade compositions including microporous cellulose sponges (MCS) and photosensitizers, aimed at enhancing temperature regulation and minimizing microbial contamination in the cold chain. Upon absorbing water, the MCS matched traditional ice in cooling efficiency and heat absorption and exhibit remarkable mechanical and thermal durability, withstanding multiple freeze-thaw cycles and compressive stresses. The cationic MCS combined with erythrosine B demonstrated strong self-sanitizing capabilities, effectively reducing microbial cross-contamination in food models. Additionally, the release rates of photosensitizers from the MCS can be modulated by altering environmental ionic strength. This research offers viable solutions to address microbial cross-contamination challenges in current cold chain systems.

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BACKGROUND: Ice is used in large quantities as refreshment in alcoholic and nonalcoholic beverages, especially in summer time. Contamination of edible ice products with pathogens is a public health concern in various countries, including Vietnam. This study aimed to assess the food safety conditions, the quality of edible ice products and related factors at manufacturing premises in Binh Phuoc Province, Vietnam in 2019. METHODS: A cross-sectional study was conducted in 2019 using both quantitative and qualitative methods. Food safety assessment was carried out in all 45 ice producing premises in the province and 79 ice samples were collected and analyzed microbiologically. In-depth interviews were conducted with 2 food safety management staff, 4 owners of premises, and 4 workers. RESULTS: Only 22.4% (18/79) and 37.8% (30/79) of the premises met requirement for food safety conditions and microbiological food safety requirements, respectively. Half of the ice samples, 51.9% (41/79), were contaminated, 49.4% (39/79) with Escherichia coli and 12.7% (10/79) with total coliforms. Streptococci, Pseudomonas aeruginosa were not detected. The major risks were material, odds ratio (OR) = 4.2 (95% confidence interval [CI]: 1.002-17.6), structural challenges in the facilities, OR = 4.3 (95% CI: 1.13-16.7), broken floors or difficulty in cleaning, OR = 5.4 (95% CI: 1.26-22.9), and poor staff hygiene practices, OR = 19.5 (95% CI: 4.2-91.1). Workers lacked knowledge and appropriate practices to prevent microbial contamination of ice products. CONCLUSIONS: The food safety conditions and the quality of ice cubes at manufacturing premises in Binh Phuoc Province were not acceptable. Hygiene deficiencies in ice producing and handling processes, inadequate knowledge of staff, inadequate food safety management practices, and hygiene conditions of the premises were important factors in producing contaminated ice products. We recommend more staff training and crediting the staff when performing adequate practices, paying attention to broken floors or difficulty in cleaning, structural deficiency, and ensuring regular monitoring of premises. This study adds a special interest to ensure food safety conditions at ice producing premises to prevent microbial contamination of the products.

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Edible flowers are a new gourmet product; however, they are not always available all years. Thus, it is essential to find out technologies to guarantee this product for a longer time. Flowers of four species (borage [Borago officinalis], heartsease [Viola tricolor], kalanchoe [Kalanchoe blossfeldiana], and dandelion [Taraxacum officinale]) were subjected to freezing (in their natural form and in ice cubes) and analyzed in terms of visual appearance, the content of flavonoids, hydrolysable tannins, phenolics, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power), and microbial quality after storage for 1 and 3 months. Flowers in ice cubes showed similar appearance to fresh ones during the 3 months of storage, whereas frozen flowers were only equivalent up to 1 month with the exception of kalanchoe. Even though flowers in ice cubes showed good appearance after 3 months of storage, they had the lowest values of bioactive compounds and antioxidant activity. On the contrary, when frozen, the content of bioactive compounds maintained or even increased up to 1 month of storage compared to fresh flowers, except for borage. Furthermore, in both freezing treatments, the microorganisms' counts decreased or maintained when compared to fresh samples, except in dandelion. In general, both treatments may allow keeping the flowers after their flowering times. PRACTICAL APPLICATION: The market of edible flowers is increasing, although they are a very perishable product with short shelf-life. Edible flowers are stored in the cold (frozen or in ice cubes); however, the effect on the bioactive compounds and microbial quality that this treatment may have on borage (Borago officinalis), heartsease (Viola tricolor), kalanchoe (Kalanchoe blossfeldiana), and dandelion (Taraxacum officinale) flowers is unknown. So, the present study was conducted to increase the knowledge about the changes that freezing treatments may have in different edible flowers. The results of the present study underline that each flower has different behavior at frozen and ice cubes storage. However, freezing flowers maintain/increase the contents of bioactive compounds, while ice cubes not. Both treatments are effective in protecting flowers from microorganism growth. So, suggesting that both freezing treatments can be used as a preservative method and may allow keeping the flowers after their flowering times.

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AIMS: To evaluate the levels of unicellular and filamentous fungi in ice cubes produced at different levels and to determine their survival in alcoholic beverages and soft drinks. METHODS AND RESULTS: Sixty samples of ice cubes collected from home level (HL) productions, bars and pubs (BP) and industrial manufacturing plants (MP) were investigated for the presence and cell density of yeasts and moulds. Moulds were detected in almost all samples, while yeasts developed from the majority of HL and MP samples. Representative colonies of microfungi were subjected to phenotypic and genotypic characterization. The identification was carried out by restriction fragment length polymorphism (RFLP) analysis of the region spanning the internal transcribed spacers (ITS1 and ITS2) and the 5·8S rRNA gene. The process of yeast identification was concluded by sequencing the D1/D2 region of the 26S rRNA gene. The fungal biodiversity associated with food ice was represented by nine yeast and nine mould species. Strains belonging to Candida parapsilosis and Cryptococcus curvatus, both opportunistic human pathogens, and Penicillium glabrum, an ubiquitous mould in the ice samples analysed, were selected to evaluate the effectiveness of the ice cubes to transfer pathogenic microfungi to consumers, after addition to alcoholic beverages and soft drinks. All strains retained their viability. CONCLUSIONS: The survival test indicated that the most common mode of consumption of ice cubes, through its direct addition to drinks and beverages, did not reduce the viability of microfungi. SIGNIFICANCE AND IMPACT OF THE STUDY: This study evidenced the presence of microfungi in food ice and ascertained their survival in soft drinks and alcoholic beverages.

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This study aimed to evaluate the levels of enteric bacteria in ice cubes produced in different environments (home-made, prepared in bars and pubs with ice machines and produced in industrial plants) and to determine their survival in different alcoholic beverages and soft drinks. Members of the Enterobacteriaceae family were found in almost all samples analysed. All industrial and the majority of home-made samples did not contain coliforms. Enterococci were not identified in domestic samples while they were detected in two industrial and three bar/pub samples. The samples collected from bars and pubs were characterized by the highest levels of enteric bacteria. Fourteen strains representing 11 species of eight bacterial genera were identified, some of which are known agents of human infections. The most numerous groups included Enterococcus and Stenotrophomonas. The survival of Enterococcus faecium ICE41, Pantoea conspicua ICE80 and Stenotrophomonas maltophilia ICE272, that were detected at the highest levels (100-400 CFU/100 mL thawed ice) in the ice cubes, was tested in six drinks and beverages characterized by different levels of alcohol, CO2, pH and the presence of antibacterial ingredients. The results showed a species-specific behaviour and, in general, a reduction of the microbiological risks associated with ice after its transfer to alcoholic or carbonated beverages.

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