Recent Listeria Outbreak Linked to Deli Meats: Top Herbal Remedies Showing Promise

Last Wednesday, the Centers for Disease Control and Prevention reported a listeria outbreak linked to deli meats, resulting in five deaths. The outbreak highlights the ongoing challenges in ensuring food safety, particularly with ready-to-eat products (1).

Listeria monocytogenes, the bacteria responsible for listeriosis, can contaminate ready-to-eat foods, including deli meats and cheeses, which are often stored at cool temperatures where listeria can still thrive. It can spread between meats, surfaces, and handling of items. It is also found in improperly handled or stored soft cheeses and milk. 

Risk and Affected Population

While anyone can contract listeriosis, it poses a higher risk to certain groups:

• Pregnant women
• Newborns
• Older adults
• People with weakened immune systems

Listeriosis can be severe and life-threatening. Symptoms include fever, muscle aches, and gastrointestinal issues. In severe cases, it can lead to septicemia and meningitis.

Natural Remedies for Listeria Infection

While antibiotics are the primary treatment for listeriosis, some natural remedies may help in the prevention and management of the infection. In studies these remedies have been found to be effective both internally and for sterilization of hands, utensils, and surfaces.

Morin

Morin, a natural flavonoid found in plants such as figs and almonds, has demonstrated efficacy in inhibiting the biofilm formation and virulence of Listeria monocytogenes (2). It achieves this without exerting harmful antibacterial pressure, making it a promising agent for reducing listeria in food environments. Studies indicate that morin can significantly extend the lifespan of organisms infected with listeria, suggesting its potential as a therapeutic supplement.

Iodine

Iodine has been shown to have antimicrobial properties that can help in reducing the bacterial load of Listeria M. A study comparing Iodine with commercial hand disinfectants used in health care found that “1% iodine showed better results against infection when compared to the other hand sanitizers”(4). Dr. Clark's Lugols Iodine

Curcumin

One 2023 study aimed to investigate the role of curcumin in promoting the clearance of Listeria monocytogenes (Lm), a pathogenic bacterium, through its effects on listeriolysin O (LLO) oligomers, both in vitro and in vivo (3).

A 2023 study demonstrated that curcumin significantly enhances the clearance of Listeria monocytogenes in infected cells and animal models (3).The primary mechanism identified involves curcumin's ability to reduce the formation of LLO oligomers. LLO is a crucial virulence factor produced by Lm that allows the bacteria to escape from the phagosome into the host cell cytoplasm. By disrupting the oligomerization of LLO, curcumin prevents the bacterium from effectively breaching host cell membranes, thereby enhancing immune clearance.

 

 In Vitro Analysis: Curcumin treatment resulted in a significant reduction in LLO oligomerization in cell culture experiments. The compound also decreased Lm viability within infected macrophages, showcasing its potential as an adjunct antimicrobial agent.

In Vivo Analysis: In murine models, curcumin administration led to a notable decrease in bacterial load in infected tissues, such as the spleen and liver. The treatment also improved survival rates among infected mice, further indicating the therapeutic potential of curcumin against Lm infections.

The study provides strong evidence that curcumin enhances the clearance of Listeria monocytogenes by inhibiting LLO oligomerization. This inhibition reduces the bacterium's ability to escape from phagosomes, thereby increasing its susceptibility to immune system eradication. These findings suggest that curcumin could be a valuable therapeutic agent for treating infections caused by Lm, especially considering its safety profile and the need for new antimicrobial strategies.

Psoraleae semen L. (Bogolji) and Sophorae radix L. (Gosam) 

The extracts of these herbs showed significant antilisterial activity comapred to a number of other herbal extracts (5). Bogolji has also shown anti-cancer promise (6) .

Garlic, Onion and Cinnamon

Numerous studies on the ability of garlic, in fresh form and extract, to combat antimicrobial resistant strains. Even more studies have been done on the synergistic effects of garlic in combination with synthetic drugs for various infections. Garlic-extract has been found to have anti-biofilm activity, (7) and anti-microbial properties against resistant strains (8). One 2020 study examined garlic essential oil, finding that "the essential oils of garlic, onion, and cinnamon show an effective antibiofilm activity against L. monocytogenes and are promising natural antimicrobial alternatives for food processing facilities" (9).

Summary

Staying informed about food safety practices and incorporating natural antimicrobial agents can aid in reducing the risk of listeria infections. For those affected, early detection and treatment are crucial to mitigate severe health outcomes. It is imporatnt to note that while natural remedies, such as herbal extracts, iodine and functional foods like garlic, have much higher safety, and in many sutdies, much higher efficacy, there is still the need to consider potential resistance to these subtances. In the studies mentioned, the opposite was found, and that especially garlic and iodine, resistance is incredibly difficult to produce. 

 

In the future, we will hopefully see a reduction in practices contributing to anti-microbial resistance, including reduciton in the use of synthetic drugs that seem to create the condition. Studies have found that hospital dumping grounds, in which multiple antibiotics into the soil, produce various antibiotic resistant microorganisms (9). 

 

 

 

References 

1. https://www.reuters.com/business/healthcare-pharmaceuticals/cdc-says-5-deaths-reported-listeria-outbreak-linked-deli-meats-2024-08-28/
2. Sivaranjani, M., Gowrishankar, S., Kamaladevi, A., Pandian, S. K., Balamurugan, K., & Ravi, A. V. (2016). Morin inhibits biofilm production and reduces the virulence of Listeria monocytogenes—An in vitro and in vivo approach. International journal of food microbiology, 237, 73-82.
3. Zhou, X., Zhang, B., Cui, Y., Chen, S., Teng, Z., Lu, G., ... & Deng, X. (2017). Curcumin promotes the clearance of Listeria monocytogenes both in vitro and in vivo by reducing listeriolysin O oligomers. Frontiers in Immunology, 8, 574.
4. Rahman, M. N., Abdullah-Al-Shoeb, M., Huq, S., & Azad, M. A. K. (2019). Assessment of antibacterial efficacy of Lugol's iodine compared with commercial hand sanitizers of Bangladesh. Journal of Life Science and Biomedicine, 9(5), 130-137.
5. https://academic.oup.com/lambio/article-abstract/55/1/47/6699626
6. Hwang, J. H., Rha, S. J., Cho, J. K., Shin, T. S., Kim, M. Y., & Kim, J. D. (2013). Psoraleae semen extract inhibits angiogenesis and adipogenesis. Biotechnology and bioprocess engineering, 18, 942-949.
7. Girish, V. M., Liang, H., Aguilan, J. T., Nosanchuk, J. D., Friedman, J. M., & Nacharaju, P. (2019). Anti-biofilm activity of garlic extract loaded nanoparticles. Nanomedicine: Nanotechnology, Biology and Medicine, 20, 102009.
8. Gupta, S., Kapur, S., DV, P., & Verma, A. (2015). Garlic: An Effective Functional Food to Combat the Growing Antimicrobial Resistance. Pertanika Journal of Tropical Agricultural Science, 38(2).
9. https://rjptonline.org/HTML_Papers/Research%20Journal%20of%20Pharmacy%20and%20Technology__PID__2022-15-3-3.html