Evaluation of Innovative Disinfection Methods for Raspberry (Rubus idaeus L.) Plant Raw Materials

Abstract

Background: Dried medicinal plant raw material, including raspberry leaves (Rubus idaeus), are widely used in the pharmaceutical, food supplements and cosmetic industries but are often contaminated with bacteria and fungi, which may pose a risk to consumer health and compromise product quality [1]. Therefore, effective yet mild disinfection strategies are required to ensure the safety and quality of plant raw material. Aim(s): To assess the effects of different disinfection methods on microbial contamination of raspberry plant raw material. Methods: Dried raspberry (Rubus idaeus L.) leaves were subjected to three disinfection treatments: pressurised CO₂ at 30 °C and 3 bar (pressure) for 1 and 24 hours, spraying with blackcurrant absolute, and spraying with cinnamon essential oil. After spraying, the plant material was air-dried for 2 hours. Microbial contamination was evaluated before and after disinfection. Data were analyzed using descriptive statistics (mean ± standard error) using Microsoft Excel. Results: Before disinfection, dried raspberry leaves showed high microbial contamination, reaching 256.67 (28.28) CFU/g. After CO₂ treatment (30 °C, 3 bar for 1 hour) microbial counts decreased to 196.2 (96.8) CFU/g. Blackcurrant absolute (Nature In Bottle, France) showed limited antimicrobial activity, with counts of 215.5 (83.3) CFU/g. Cinnamon essential oil (UAB Kvapų Namai, Lithuania) exhibited the strongest antimicrobial effect, reducing microbial contamination to 72 CFU/g. Conclusion: Among the evaluated disinfection methods, cinnamon essential oil showed the highest effectiveness in reducing microbial contamination of dried raspberry leaves, whereas CO₂ treatment demonstrated moderate effects, and blackcurrant absolute showed only limited antimicrobial activity.