Can bay leaves kill you?
Author bio
Dr Anny Manrich PhD is a food Engineer with expertise in Food Technology, Natural Polymers, Edible Films, Enzymes, and Nanotechnology. She writes and reviews content on these topics.
Dr Anny Manrich’s Highlights:
- Research and Technology at the Brazilian Agricultural Research Corporation
- PhD in Chemical Engineering with a focus on Biochemistry at the Federal University of Sao Carlos/ Brazil and a one-year scholarship at the Technical University of Munich/ Germany
- Bachelor of Food Engineering at the University of Campinas/ Brazil and a one-year scholarship at the Technical University of Munich/ Germany
“To solve a problem, global vision and multifactorial understanding are necessary. Therefore, in addition to expertise, one should seek multidisciplinary thinking connected with science and reality” – Dr Anny Manrich, PhD.
Professional Experience:
Dr Anny Manrich’s Experience Joining the Brazilian Agricultural Research Corporation, as soon as she completed her doctorate,
Dr Anny Manrich has worked on several projects, including the more than three-year partnership project with BRF, a major food producer in Brazil. As a postdoctoral fellow.
Dr Anny Manrich has also contributed to several business consultancies and research projects of the National Nanotechnology Laboratory System in areas such as food technology, fibres, films and coatings and Nanotechnology; in a very determined way, having a great team relationship, being creative and committed.
Growing concerns about the safe introduction of nanomaterials into today’s life emphasises the need to create regulatory documentation in front of characterising, using and testing them. Dr Anny Manrich worked for two years on a characterization project for nanoscale materials, with the aim of exploring their possible health effects.
Despite not having specific academic training in packaging or polymeric films, Dr Anny Manrich works at the Brazilian Agricultural Research Corporation in areas of edible and biodegradable films produced from agricultural waste and in the development of films with greater resistance to water, having articles published in renowned scientific journals, which demonstrates her multidisciplinary understanding and creativity.
In addition, she worked for four years as a consultant to a food company to develop a line of snacks that are healthy and that add functional ingredients, physiologically active compounds that bring health benefits, made from fruits and vegetables, enabling diet improvement, disease prevention and reduction of nutritional deficiencies.
Dr Anny Manrich participated as a member of the examination board for two Master’s exams and one PhD exam at the Department of Chemical Engineering of the Federal University of São Carlos.
Education:
- 2001 Bachelor in Food Engineering at the State University of Campinas, Brazil
- 1999 One year scholarship at the Technical University of Munich
- 2004 Master in Chemical Engineering at the Federal University of São Carlos, Brazil
- 2012 PhD in Chemical Engineering at the Federal University of São Carlos, Brazil
- 2010 One year scholarship at the Technical University of Munich
The main publications of Dr. Anny Manrich are:
Articles
Manrich, A., Moreira, F. K., Otoni, C. G., Lorevice, M. V., Martins, M. A., & Mattoso, L. H. (2017). Hydrophobic edible films made up of tomato cutin and pectin. Carbohydrate Polymers, 164, 83-91.
Mendes, J. F., Norcino, L. B., Martins, H. H. A., Manrich, A., Otoni, C. G., Carvalho, E. E. N., … & Mattoso, L. H. C. (2020). Correlating emulsion characteristics with the properties of active starch films loaded with lemongrass essential oil. Food Hydrocolloids, 100, 105428.
Norcino, L. B., Mendes, J. F., Natarelli, C. V. L., Manrich, A., Oliveira, J. E., & Mattoso, L. H. C. (2020). Pectin films loaded with copaiba oil nanoemulsions for potential use as bio-based active packaging. Food Hydrocolloids, 106, 105862.
Manrich, Anny, et al. Immobilization of trypsin on chitosan gels: Use of different activation protocols and comparison with other supports. International Journal of Biological Macromolecules 43.1 (2008): 54-61.
Manrich, Anny; Komesu, Andrea ; Adriano, Wellington Sabino; Tardioli, Paulo Waldir ; Giordano, Raquel Lima Camargo . Immobilization and Stabilization of Xylanase by Multipoint Covalent Attachment on Agarose and on Chitosan Supports. Applied Biochemistry and Biotechnology, v. 161, p. 455-467, 2010.
Mendes, J. F., Martins, J. T., Manrich, A., Neto, A. S., Pinheiro, A. C. M., Mattoso, L. H. C., & Martins, M. A. (2019). Development and physical-chemical properties of pectin film reinforced with spent coffee grounds by continuous casting. Carbohydrate polymers, 210, 92-99..
Milessi, T. S., Kopp, W., Rojas, M. J., Manrich, A., Baptista-Neto, A., Tardioli, P. W., … & Giordano, R. L. (2016). Immobilization and stabilization of an endoxylanase from Bacillus subtilis (XynA) for xylooligosaccharides (XOs) production. Catalysis Today, 259, 130-139.
Mendes, J. F., Norcino, L. B., Manrich, A., Pinheiro, A. C. M., Oliveira, J. E., & Mattoso, L. H. C. (2020). Development, physical‐chemical properties, and photodegradation of pectin film reinforced with malt bagasse fibers by continuous casting. Journal of Applied Polymer Science, 137(39), 49178.
Mendes, J. F., Martins, J. T., Manrich, A., Luchesi, B. R., Dantas, A. P. S., Vanderlei, R. M., … & Martins, M. A. (2021). Thermo-physical and mechanical characteristics of composites based on high-density polyethylene (HDPE) e spent coffee grounds (SCG). Journal of Polymers and the Environment, 29, 2888-2900..
Mendes, J. F., Norcino, L. B., Martins, H. H., Manrich, A., Otoni, C. G., Carvalho, E. E. N., … & Mattoso, L. H. C. (2021). Development of quaternary nanocomposites made up of cassava starch, cocoa butter, lemongrass essential oil nanoemulsion, and brewery spent grain fibers. Journal of Food Science, 86(5), 1979-1996.
Manrich, A., Martins, M. A., & Mattoso, L. H. C. (2021). Manufacture and performance of peanut skin cellulose nanocrystals. Scientia Agricola, 79.
Nascimento, V. M., Manrich, A., Tardioli, P. W., de Campos Giordano, R., de Moraes Rocha, G. J., & Giordano, R. D. L. C. (2016). Alkaline pretreatment for practicable production of ethanol and xylooligosaccharides. Bioethanol, 2(1)..
Manrich, Anny, de Oliveira, J. E., Martins, M. A., & Mattoso, L. H. C. Physicochemical and Thermal Characterization of the Spirulina platensis. J. Agric. Sci. Technol. B, v. 10, p. 298-307, 2020.
Book Chapter
Terra, I. A. A., Aoki, P. H., Delezuk, J. A. D. M., Martins, M. A., Manrich, A., Silva, M. J., … & Miranda, P. B. (2022). Técnicas de Caracterização de Polímeros. Nanotecnologia Aplicada a Polímeros, 614.
Conference Papers
Ferreira, L. F., Luvizaro, L. B., Manrich, A., Martins, M. A., Júnior, M. G., & Dias, M. V. (2017). Comparação da estabilidade de suspensões poliméricas de amido/tocoferol e quitosana/tocoferol. In: CONGRESSO BRASILEIRO DE POLÍMEROS, 14., 2017, Águas de Lindóia, SP.
Manrich, A., Hubinger, S. Z., & Paris, E. C. (2017). Citotoxicidade causada por nanomateriais: avaliação do micronúcleo. In: WORKSHOP DA REDE DE NANOTECNOLOGIA APLICADA AO AGRONEGÓCIO, 9., 2017, São Carlos. Anais… São Carlos: Embrapa Instrumentação, 2017. p. 655-658.
Manrich, Anny, et al. Immobilization and Stabilization of Xylanase by multipoint covalent attachment on Glyoxyl Agarose Support. The 31st Symposium on Biotechnology for Fuels and Chemicals. 2009.
Manrich, Anny, et al. Application of immobilized xylanase on hydrolysis of soluble wood hemicelluloses after using microwave and organosolv pre-treatments. The 32nd Symposium on Biotechnology for Fuels and Chemicals. 2010.
You can view some of Dr Anny’s work below and links to her professional profile.
Research Gate: https://www.researchgate.net/profile/Anny-Manrich-2
Scopus: https://www.scopus.com/authid/detail.uri?authorId=23103497100
Google Scholar: https://scholar.google.com/citations?hl=en&user=Ea9qpr0AAAAJ
Linkedin: https://br.linkedin.com/in/anny-manrich-20693129
In this article, we will answer the following question: Can bay leaves kill you? We will tell you which types of bay leaves are edible and which types are dangerous. We will also talk about the use of bay leaf in the kitchen and how to store it long term.
Can bay leaves kill you?
No, bay leaves are non-toxic in nature and consumption is non-threatening to humans. However, the bay leaf remains very stiff even after cooking, thus can lead to indigestion or digestive problems. It can also become a choking hazard.
Acaricidal activity of bay leaf oils was observed against Psoroptes cuniculi. Acaricidal activity of bay oil led to a mortality rate of 73% at a concentration of 10% and at 5% average activity was considerably reduced to 51% (6).
The leaves produced by Laurus nobilis are non-toxic. However, certain species with the name “laurel” or “bay” can be really poisonous and should be avoided, while others can be perfectly safe. Don’t take chances if you’re not sure. Limit cooking with bay leaves to those available in supermarkets or that you grow yourself.
Bay laurel (Laurus nobilis), also known by various names such as: bay leaf, sweet bay leaf, Greek bay leaf, or true bay leaf, is prized for its aromatic leaves that add a distinctive flavor to a variety of hot dishes (1). However, this delicious Mediterranean tree has a reputation for being toxic. What is the real truth about bay leaves? Are they poisonous? What laurels are edible? Can you cook with all the bay leaves, or are some bay leaves toxic? Let’s explore the topic.
Bay leaves and their essential oil do not appear to have any significant toxicity. However, sporadic reports have indicated that bay leaves may cause allergic contact dermatitis perhaps induced by one or more sesquiterpene lactone present in the plant composition. Certain bay leaf samples of Mexican origin had been detected to be infested with gastrointestinal disease causing Clostridium perfringens spores (1).
The consumption of moderate amounts of bay leaves is recommended because some compounds of the essential oil present in the leaves can easily overcome the blood–brain barrier. Therefore, an excessive uptake of these compounds can cause confusion and neurological disorders in adults and more serious problems in children. Several cases of intoxication due to leaves and fruits of laurel have been reported in Italy, mainly involving children (2).
About edible bay leaves
So which bay leaves are edible? Royal bay leaves (Laurus nobilis) are safe, but the leathery leaves, which can be sharp at the edges, should always be removed from the plate before serving.
Additionally, the following “bay” plants are also considered safe. Like Laurus nobilis, they are all within the Lauraceae family:
West Indian bay leaf (Pimenta racemosa), is found on the various islands of the West Indies, but most particularly in Dominica andcontains the following chemicals: 10-hydroxy octacosanol tetradicanoate, l-docosanol tetradecanoate and 11-gaveeramanthin, dehydrocostus lactone, costunolide, zalu zanin and sesquiterpene alcohol (1).
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California laurel (Umbellularia californica), also known as Oregon myrtle or pepper wood, is safe to use for culinary purposes, although the flavor is spicier and more intense than Laurus nobilis. The leaves of U. californica contain, as major volatile constituent, the monoterpene ketone umbellulone, a compound endowed with a strong, camphor-like odour that, when extracted from the leaf oil and administered to laboratory animals, affects respiration, heartbeat and blood circulation, eventually causing death. It can induce some individuals to headache (4).
Inedible bay leaves
Beware of the toxic trees in the bay. The following trees have toxic compounds and are inedible. They may have similar names and the leaves may look like regular bay leaves, but they belong to completely different plant families and are not related to bay.
Mountain laurel (Kalmia latifolia): All parts of the plant are toxic. Even honey made from the flowers can induce gastrointestinal pain if eaten in large quantities. Plants of the genus Kalmia contain diterpene grayanotoxins. Consumption of grayanotoxin containing leaves, flowers or secondary products as honey may result in intoxication specifically characterized by dizziness, hypotension and atrial-ventricular block. Symptoms are caused by an inability to inactivate neural sodium ion channels resulting in continuous increased vagal tone (3).
Cherry laurel (Prunus laurocerasus): All parts of the plants are toxic and can cause life-threatening respiratory problems. Cherry laurel leaves, morphologically similar to those of laurel, contain toxic cyanogenic glycosides. Both humans and animals are susceptible to any damage resulting from the release of hydrogen cyanide after the ingestion of this plant (2).
Note: Although bay leaves are safe when used in small amounts, they can be toxic to horses, dogs, and cats. Symptoms include diarrhea and vomiting.
How to use bay leaf?
In the Middle Ages, bay leaves were used as medicine and as an insecticide, but also in the kitchen, where they were used to prepare meat roasts, soups, broths, and sauces; just as we continue to do in the XXI century.
Perhaps less common is their use to flavor a good bean dish, and they go especially well with lentils. It is also highly recommended to use it when our dishes ask for cloves as the bay leaves help to balance and enhance the flavor of this spice.
If we want to use the bay leaf in sweet dishes, it goes very well in puddings and ice creams, which greatly enhance the flavor and aroma of laurel, allowing us to taste it in a better way, since its properties are not overshadowed by those of other ingredients.
In addition, it is important to know that bay leaves should be treated as if they were a spice, considering that spices are more harmonious than aromatic herbs and can be combined more easily. Let us remember that bay leaves make a dish more complex and interesting; It may not be the most important, but it ensures to turn it into a party of flavor.
Although it is not very common to find fresh bay leaves, it is always necessary to bear in mind that its eucalyptus flavor is much more powerful when it is fresh than when the leaves are dry. Thus, fresh bay leaves are much better when used in desserts, providing a touch of freshness.
Also, it is necessary to remember that bay leaves grow in very dry sunny climates, like oregano or rosemary, so they retain their flavor better after they dry, unlike what happens with other herbs such as coriander, parsley, or basil.
How to store bay leaf?
The preservation of the aroma and flavor properties of spices and aromatic herbs depends a lot on how we store them, so it is recommended to use them for a period of 3-6 months in order to get the most out of them (5).
We must try to keep them in a hermetically closed glass jar, and if we want to keep them for many years, it is best to keep them in the freezer.
The bottom line
We remind you that the following types of bay leaves can be dangerous:
- Mountain laurel (Kalmia latifolia)
- Cherry laurel (Prunus laurocerasus)
And that the following types of bay leaves are safe to consume:
- Indian bay leaf (Cinnamomum tamala)
- Mexican bay leaf (Litsea glaucescens)
- California laurel (Prunus laurocerasus)
If you have any comments or questions on the content, please let us know!
References
- Peter, Kuruppacharil V., ed. Handbook of herbs and spices: volume 3. Woodhead publishing, 2006.
- Malaspina, Paola, et al. Risk of poisoning from garden plants: misidentification between laurel and cherry laurel. Toxins, 2022, 14, 726.
- Jansen, Suze A., et al. Grayanotoxin poisoning:‘mad honey disease’and beyond. Cardiovasc toxicol, 2012, 12, 208-215.
- Benemei, S., G. Appendino, and P. Geppetti. Pleasant natural scent with unpleasant effects: cluster headache-like attacks triggered by Umbellularia californica. Cephalalgia, 2010, 30, 744-746.
- Riley J. Selecting, Storing, and Using Fresh Herbs. Ohio State University. 2021.
- Batool S, Khera RA, Hanif MA, Ayub MA. Bay Leaf. Medicinal Plants of South Asia. 2020, 63-74.
