Pennywort (Centella asiatica) is a herbaceous vegetable commonly consumed raw as ‘ulam’ or salad. Consumption of raw leafy green vegetables is one of the pathogenic mechanisms that could cause foodborne outbreaks. The aim of the present work was therefore to investigate the effect of pulsed light (PL) treatment at fluences of 1.5, 4.2, 6.9, 9.6, and 12.3 J/cm² on the microbiological and physical quality of pennywort stored at 4 ± 1°C. Escherichia coli (E. coli) were inoculated onto the pennywort leaves before being exposed to PL and viewed using scanning electron microscopy (SEM). PL fluences of 6.9, 9.6, and 12.3 J/cm² significantly reduced the microbial count; however, the highest inactivation was obtained by using fluences of 9.6 and 12.3 J/cm². The color of pennywort was not significantly affected by PL treatment applied at lower fluences of 1.5, 4.2, and 6.9 J/cm²; however, at higher fluence, 9.6 and 12.3 J/cm², the color was affected. PL at 1.5, 4.2, 6.9, and 9.6 J/cm² was able to retain the texture appearance of the leaves. To conclude, PL at 6.9 J/cm² showed the best fluence to reduce total aerobic mesophilic count while retaining the physical properties of pennywort leaves and extend the shelf life to about four days. The inactivation of E. coli population was significantly higher at PL fluence of 6.9 J/cm². It was observed that PL caused the destruction to the surface of E. coli’s cell membrane. The reductions of samples inoculated with E. coli were better than those achieved in native microbiota. Furthermore, the present work also demonstrated that PL treatment was able to reduce the microbial count on pennywort leaves.
Bio-cellulose is the microbial extracellular cellulose that is produced by growing several microorganisms on agriculture by-products, and it is used in several food applications. This study aims to utilize sago by-product, coconut water, and the standard medium Hestrin-Schramm as the carbon sources in the culture medium for bio-cellulose production. The bacteria Beijerinkia fluminensis WAUPM53 and Gluconacetobacter xylinus 0416 were selected based on their bio-cellulose production activity. The structure was determined by Fourier transform infrared spectroscopy and scanning electron microscopy, while the toxicity safety was evaluated by brine shrimp lethality test. The results of Fourier transform infrared spectroscopy showed that the bio-cellulose produced by B. fluminensis cultivated in sago by-products was of high quality. The bio-cellulose production by B. fluminensis in the sago by-product medium was slightly higher than that in the coconut water medium and was comparable with the production in the Hestrin-Schramm medium. Brine shrimp lethality test confirmed that the bio-cellulose produced by B. fluminensis in the sago by-product medium has no toxicity, which is safe for applications in the food industry. This is the first study to determine the high potential of sago by-product to be used as a new carbon source for the bio-cellulose production.
The function of packaging is crucial in the maintenance of fresh meat product quality. This study aimed to assess the efficiency of six films added with coatings 2379L/220 and 2379L/221 (containing sage extracts) to inhibit Salmonella typhimurium, Staphylococcus aureus, and Escherichia coli, which showed that two of the six films had a significant effect. Additionally, the effects of the films on refrigerated skinless chicken breast meat were evaluated based on microbiological content, colour, weight loss, texture and pH. Four of the six films were examined could extend the storability of refrigerated chicken breast fillets for up to seven days. All six treated films improved the pH, colour stability, weight loss, and texture of the chicken fillets. Therefore, these findings suggested that the coatings containing sage extracts having different viscosities (2379L/220 and 2379L/221) were effective as antimicrobial adhesives in food packaging films and can be commercially applied in prolonging the storage of chicken breast meat without affecting their quality.