The Antibacterial Effect of the Films Coated with the Layers Based on Uncaria tomentosa and Formitopsis betulina Extracts and ZnO Nanoparticles and Their Influence on the Secondary Shelf-Life of Sliced Cooked Ham

Abstract

Microbial surface contamination of the cooked ham sliced by shop assistants has an influence on its potential secondary shelf-life. Active packaging may be the solution. The first goal of the work was to obtain coatings based on Formitopsis betulina and Uncaria tomentosa extracts (separately), with the addition of nanoparticles of ZnO (as a synergetic agent to increase plant extracts’ antimicrobial effectiveness), that could be active against selected bacterial strains. Another aim of the work was to determine the influence of obtained active layers on microbial purity and texture of the samples. The results of the study demonstrated that the layers containing F. betulina or U. tomentosa extracts with the addition of ZnO nanoparticles inhibited Staphylococcus aureus, Bacillus atrophaeus, and Escherichia coli growth completely and decreased the number of Pseudomonas syringae cells. Analyzing microbial purity of sliced cooked ham portions after storage, it was observed that the active packaging based on U. tomentosa extracts had a greater influence on the total count than the coatings containing F. betulina extracts and that both active packaging materials affected the microbial purity of the cooked ham. Analyzing the textural parameter changes after 48 h of storage, a decrease in the gumminess, chewiness and cohesiveness values was noted, but only for the ham portions stored in bags covered with the coating based on U. tomentosa. The effectiveness of the active packaging on textural parameters after 96 h of storage was not noticed.

The Antifungal and Antiviral Activity of Coatings Containing Zinc Oxide Nanoparticles and Verbascum L. or Formitopsis betulina Extracts and Their Influence on the Quality of Strawberries after Storage

“…The authors' [10] findings led to the theory that the introduction of the ZnO nanoparticles (separately) into the F. betulina or into the Verbasculum L. or the U. tomentosa extracts may cause a synergistic effect between two active agents. Other experiments carried out by the authors [26] also confirmed these assumptions. The coatings including F. betulina or U. tomentosa extracts with zinc oxide nanoparticles as active agents, which were found to be highly active against Staphylococcus aureus, Escherichia coli and B. atrophaeus cells.…”

“…It was also concluded in a previous work that a Ut active coating was able to display a greater effect on the growth of bacteria than an Fb coating, though for a shorter time [26]. Due to their antibacterial effectiveness, they were also confirmed as retaining the quality and freshness of slices of cooked ham during secondary shelf-life (48 h) [26]. This is why the ZnVL and ZnFb active layers (more effective than ZnUt layer), which exhibit antibacterial and antifungal properties, were selected to preserve the strawberries during these storage tests.…”

“…The findings of the previous study confirmed that these coatings were also active against bacterial strains such as S. aureus, E. coli and B. atrophaeus. It was also concluded in a previous work that a Ut active coating was able to display a greater effect on the growth of bacteria than an Fb coating, though for a shorter time [26]. Due to their antibacterial effectiveness, they were also confirmed as retaining the quality and freshness of slices of cooked ham during secondary shelf-life (48 h) [26].…”

“…As an assumption [9,10,26], it might be predicted that the introduction of ZnO nanoparticles into the F. betulina, Verbascum L. or U. tomentosa extracts (separately) might lead to antifungal and antiviral activity of the layers on the packaging material surfaces. The coatings containing zinc oxide nanoparticles as an additive will be UV resistant due to their UV-shielding properties, and they will maintain the plant extracts' active compound effectiveness [12,[16][17][18][19][20].…”

Synthesis of organic–inorganic hybrid nanocomposites modified by catalase-like catalytic sites for the controlling of kiwifruit bacterial canker

“…First, low-cost commercial ZnO NPs serve as the active core of nanocomposite against Psa . 50–54 In addition, the incorporation of PDA ensures uniform deposition of the metal enzyme-like active sites on the surface, enhancing biocompatibility. 55 The nanocomposites, with excellent CAT-like activity, exhibit K m and V ma x values superior to that of most reported nanozymes, efficiently converting H 2 O 2 into O 2 .…”