A New Approach to Food Package Decontamination
The WHO reports that the incidence of foodborne disease is closely linked to low- and middle-income countries but is still a growing health issue around the globe (1). Currently, worldwide about 1 in 10 people (600 million) fall ill from a foodborne illness and approximately 420,000 people die from these diseases each year (2). This has caused researchers to spend more time looking for innovative solutions to the issue of foodborne illness.
In the Journal of Food Engineering, researchers Luksiene and Paskeviciute (2011) studied the possibility of inactivating certain food pathogens, their spores, and bioﬁlms on the surface of a polyoleﬁne packaging material using sodium chlorophyllin (Na-Chl)-based photosensitization. They also wanted to compare the efﬁciency of this treatment with conventional antimicrobial methods (3).
Foodborne pathogens are typically eliminated with some type of thermal treatment during initial food processing (e.g., pasteurization or sterilization) (4). Which means the presence of pathogens found on the food or its packaging after initial food processing means there was possible contamination during post-processing steps (through packaging surfaces, equipment, etc.) Luksiene and Paskeviciute decided to focus on the contamination of food packaging.
They cited that food packaging contamination is composed mostly of Bacillus (B.) cereus and its spores which are highly resistant to antibacterial treatments (5). In addition, Listeria (L.) monocytogenes were found on the surfaces of food processing equipment (3). Conventional methods of thermal sterilization can inactivate surface-attached pathogens but does not have the same effect on heat-sensitive packaging materials. They researched many non-thermal sterilization methods; however, these methods were often too costly or are not sensible for wider application (3).
Luksiene and Paskeviciute determined that photosensitization was a possible new approach to decontaminating food packaging surfaces from microorganisms. They noted an advantage of photosensitization is the absence of any bacterial resistance, compared to other antibacterial treatments. They chose to use sodium chlorophyllin (Na-Chl)-based photosensitization because chlorophyll and its derivatives are widely known photosensitizers. Na-Chl has also exhibited antimutagenic and anticarcinogenic properties, as well as a high antioxidant capacity (3).
Study results indicated that both B. cereus and L. monocytogenes were effectively inactivated by Na-Chl-based photosensitization in vitro and on the surface of polyoleﬁne food packaging (3). Na-Chl inactivated gram-positive bacteria very quickly (2 minutes). Comparatively, gram-negative Salmonella typhimurium needs approximately 60 minutes with Na-Chl to produce inactivation after photosensitization treatment. They also found that it only required a low concentration of Na-Chl to inactivate B. cereus and L. monocytogenes in vitro (3). Thermo-resistant B. cereus and L. monocytogenes strains, spores, and biofilms had a slower inactivation rate and needed about 30 minutes of illumination (3).
Luksiene and Paskeviciute also compared Na-Chl photosensitization with more traditional contamination methods. Photosensitization was much more effective against B. cereus and L. monocytogenes attached on surfaces than washing with water or 200 ppm Na-hypochlorite (3).
Ultimately, the data shows that Na-Chl-based photosensitization may serve as an effective human and environmentally friendly technique to decontaminate food packaging.
Access the full study here: https://www.academia.edu/33333558/Reprint_of_Novel_approach_to_decontaminate_food_packaging_from_pathogens_in_non_thermal_and_not_chemical_way_Chlorophyllin_based_photosensitization
(1) Foodbourne Diseases. (2021). World Health Organization. https://www.who.int/health-topics/foodborne-diseases#tab=tab_2
(2) Food Safety: Key Facts. (April 30, 2020). World Health Organization. https://www.who.int/news-room/fact-sheets/detail/food-safety
(3) Luksiene, Z., & Paskeviciute, E. (2011). Novel approach to decontaminate food-packaging from pathogens in non-thermal and not chemical way: Chlorophyllin-based photosensitization. Journal of Food Engineering, 110, 317-323. www.elsevier. com/locate/jfoodeng
(4) Difference Between Pasteurization and Sterilization. (May 10, 2016). PEDIAA. https://pediaa.com/difference-between-pasteurization-and-sterilization/
(5) Nicholson, W.L., Munakata, N., Horneck, G., Melosh, H.J., & Setlow, P. (2000). Resistance of Bacillus endospores to extreme terrestrial and extraterrestrial environments. Microbiology and Molecular Biology Reviews 64, 548–572. https://doi.org/10.1128/mmbr.64.3.548-572.2000