Vaccines In Food

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Pharma Crops: What Happens When Food Becomes A Vaccine Factory?

Food has always occupied a clear and deeply understood role in human life. It nour­ishes, sustains and connects families to land and tradition. It also has long been used medicinally in the form of herbal remedies, healing broths, fermented foods and other traditional practices that support the body’s natural resilience. Mod­ern pharmaceutical medicine, by contrast, has historically belonged to a different category al­together—something manufactured, regulated, prescribed and administered. But over the last several decades, those lines have begun to blur.

Quietly, and largely outside of public aware­ness, biotechnology companies and researchers have been engaging in “molecular farming,” developing genetically engineered plants— nicknamed “pharma crops”—designed not simply to feed people but to produce medically active substances inside living crops. Tobacco, potatoes, tomatoes, corn, rice, lettuce and other plants have been used to manufacture vaccine antigens, antibodies, hormones and other biologically active compounds. Attracting particular enthusiasm, “edible vaccines”¹ are at the forefront of this technology.

PROMISED BENEFITS

Many edible vaccines are designed as “sub­unit” vaccines.² In the case of plant-based edible vaccines, this means introducing selected genes into the plants so that the crops produce specific proteins intended to trigger an immune response.³

Supporters describe pharma crops and edible vaccines as “inno­vative” solutions to global challenges in vaccine manufacturing and distribution.¹ Plants, they argue, could serve as inexpensive biological factories producing vaccines on a massive scale. Other claimed advan­tages include easier administration and transport, reduced dependence on syringes and refrigeration, and broader access in countries or regions where conventional cold-chain systems and consistent medical access are problematic. Researchers are also exploring whether immune protection from edible vaccines might pass from vaccinated mothers to infants dur­ing pregnancy or through breastfeeding.

However, beneath the exuberant promises lies a troubling reality. Turning food crops into drug-delivery systems raises profound scientific, agricultural, regulatory and ethical concerns. For example, what happens when biologically active substances designed to alter immune function are grown outdoors in the same open agricultural systems that supply the global food chain? Once pharmaceutical production moves beyond the controlled environment of a laboratory, questions of contamination, cross-pollination, environmental spread, dosage control, informed consent and long-term safety become extremely pertinent yet difficult to answer.

SOME HISTORY

The effort to use plants as pharmaceutical production systems began gaining momentum in the late 1980s. In 1989, researchers led by Dr. Andrew Hiatt demonstrated that genetically engineered tobacco plants could produce functional antibodies, establishing the scenario that plants might serve as living manufacturing platforms for medically active compounds.^4,5 Soon after­ward, scientists engineered tobacco plants to express antigens associated with Streptococcus mutans, the bacterium linked to tooth decay.^1,3,6

By the late 1990s, interest in plant-made pharmaceuticals had expanded rapidly. Molecu­lar biologists like Dr. Charles Arntzen, professor and founding director of the Biodesign Institute at Arizona State University, became leading advocates for the emerging edible vaccine field, attracting significant scientific, government and commercial interest. Some of the most widely publicized experiments involved potatoes en­gineered to produce hepatitis B antigens, fol­lowed by studies involving the Norwalk “virus,” cholera toxin and enterotoxigenic E. coli toxins.⁷ As enthusiasm grew, researchers even moved beyond laboratory and animal studies into small human trials in which volunteers consumed raw potatoes genetically engineered to express antigens associated with these pathogens.⁸

Additional studies in the early 2000s reinforced interest in the field. Researchers like Francesco Sala at the University of Milan published findings suggesting that proteins pro­duced inside genetically engineered plants could stimulate mucosal immune responses following oral administration.⁹ Guided by germ theory and the idea that infectious pathogens enter the body through the mucosal surfaces lining the mouth, nose, lungs and digestive tract, scientists posited that vaccine antigens delivered through food would trigger immune protection directly at those entry points.

As scientists investigated plant-based vaccines targeting a wide range of human and animal diseases (including influenza, rabies, measles, malaria, cancer, anthrax, HIV and foot-and-mouth disease) and continued to explore plants as production systems for antibodies and other biologically active compounds, they found that translating the concept of edible vaccines into a reliable and controllable product was proving difficult. They discovered that vaccine proteins produced inside plants could degrade during digestion, and antigen expression often varied significantly from plant to plant, even within the same crop, raising concerns about inconsistent dosing.¹

Even so, interest in molecular farming ac­celerated dramatically during the Covid era, with governments, universities and biotech companies viewing plants as potential rapid-response production platforms for pandemic countermeasures and next-generation biologics. One of the most widely publicized examples was the Covid vaccine developed by Quebec-based biotech firm Medicago, a privately owned subsidiary of Mitsubishi Chemical Group until Mitsubishi shut it down in 2023,¹⁰ shortly after buying out all of the shares owned by second­ary investor (and tobacco giant) Philip Morris.¹¹ Medicago had been working on a tobacco-based influenza vaccine since 2012.¹² Continuing with this branch of research, Medicago used tobacco relative Nicotiana benthamiana to produce a Covid vaccine candidate called Covifenz. In February 2022, Canada authorized Covifenz for human use,^13,14 although that authorization was later withdrawn at the company’s request.

In addition to tobacco-based vaccines, re­searchers have continued to explore plant-based technologies involving lettuce and spinach. This work includes efforts to produce spike proteins and related compounds within plant systems.^1,3 Scientists at the University of California, River­side, for example, announced in 2021 that they were investigating whether edible plants could potentially be used to manufacture materials associated with mRNA vaccine technology.¹⁵

Over time, the technologies underly­ing pharma crops have become increasingly sophisticated.^1,3 Some approaches rely on the theorized promise of “stable” genetic trans­formation, in which pharmaceutical genes become permanently integrated into a plant’s DNA and are passed on through seeds into future generations. Other systems use transient expression techniques that temporarily convert plant leaves into short-term protein-producing factories through modified plant “viruses” or Agrobacterium-based delivery methods. More specialized platforms include chloroplast en­gineering, hydroponic production systems and plant cell suspension cultures grown inside enclosed bioreactors designed to function more like controlled manufacturing facilities than conventional farms.

IS THE GENIE OUT OF THE BOTTLE?

Notwithstanding the decades of experi­mentation and significant public-private invest­ments, the promise of edible vaccines has not fully materialized. Back in 2018, Mitsubishi Chemical/Medicago was eagerly anticipating that its tobacco-based flu vaccine would earn over seven hundred million dollars in annual sales¹² by 2020; instead, the subsidiary is now closed. Most pharma crop technologies remain confined to laboratories, greenhouses or tightly controlled production environments.

At the same time, that scientists aspire to transform agriculture into a platform for phar­maceutical manufacturing is unmistakable. Moreover, several plant-derived biologic prod­ucts and therapeutics have achieved regulatory approval, particularly in specialized medical and veterinary applications.

Worryingly, the public has little practical ability to know where pharma crops are being developed, what compounds they are being engineered to produce or whether experimen­tal traits may have escaped into conventional agricultural systems.⁴ One need only consider the story of StarLink corn to understand the threat posed by contamination.¹⁶ In 2000, the genetically engineered corn variety—which had been approved only for animal feed because of unresolved allergy concerns—was discovered in taco shells and other human food products across the United States. The contamination triggered widespread recalls, export disruptions and public controversy after the corn had spread through grain handling and processing systems despite regulatory restrictions intended to keep it segregated. The incident clearly demonstrated the difficulty of preventing genetically engi­neered traits from entering the broader food supply in a commodity agriculture system.

Just two years later, in 2002, an even more direct warning emerged. Biotechnology compa­ny ProdiGene was found to have contaminated nearby soybean crops with genetically engi­neered corn grown to produce a protein intended for a pig vaccine.¹⁷ Federal regulators intervened and ordered the quarantine and destruction of approximately five hundred thousand bushels of soybeans, and ProdiGene later paid civil penal­ties and cleanup costs. Although the contamina­tion was said to have been identified before the soybeans reached consumers, the incident again exposed the fragility of containment measures.

Unlike enclosed greenhouses, bioreactors or tightly controlled laboratory environments, crops grown outdoors in open agricultural fields introduce an entirely different level of unpre­dictability.¹⁸ Open fields are not sealed pharma­ceutical manufacturing facilities. Seeds can spill during planting, harvesting or transportation. “Volunteer” plants may emerge unexpectedly in subsequent growing seasons from seeds left behind in the soil. Pollen can drift beyond field boundaries, carried by wind, insects, weather patterns or farm equipment. Meanwhile, grain from countless farms routinely moves through an immense commodity infrastructure in which crops are harvested, stored, transported and pro­cessed in shared systems. Once biologically ac­tive pharmaceutical compounds are introduced into open agricultural environments, maintain­ing strict containment becomes extraordinarily difficult.

The Union of Concerned Scientists exam­ined these concerns in detail in a 2004 report,¹⁹ which concluded that the structure of modern American commodity agriculture was funda­mentally incompatible with the degree of seg­regation pharmaceutical crops would require. After reviewing how major commodity crops such as corn and soybeans move through the agricultural system, the organization warned that the commodity crop infrastructure was engineered around bulk handling and large-scale commingling, not for the precise isolation standards required to prevent pharmaceutical contamination of the food and animal feed supply.

The report also identified numerous path­ways through which contamination could oc­cur. Cross-pollination represented one major concern, particularly with crops such as corn, whose pollen can travel significant distances even under normal field conditions. However, the researchers emphasized that contamination risks extended far beyond pollen drift alone. Shared combines, grain elevators, transport trucks, rail cars, storage bins and processing facilities all create opportunities for acciden­tal mixing. Even trace amounts of residual plant material left behind in equipment or storage systems could potentially introduce pharmaceutical-producing material into con­ventional food channels. Because crops from multiple farms routinely converge throughout every stage of the supply chain, the research­ers concluded that maintaining extremely low contamination thresholds for pharmaceutical-producing food crops—or tracing and isolating contamination—would likely be impossible to guarantee under ordinary commercial farming conditions.¹⁹

BIOLOGICAL AND REGULATORY CONCERNS

Concerns extend beyond environmental escape alone. Vaccine antigens and other phar­maceutical proteins are specifically engineered to produce biological effects. In controlled pharmaceutical manufacturing environments, developers can (at least in theory) attempt to standardize dosage, monitor contaminants and maintain batch consistency. Food systems do not offer comparable safeguards. If pharma­ceutical-producing crops were to contaminate food or feed supplies, serious questions would immediately arise regarding potency, cumula­tive exposure, vulnerable populations and the long-term effects of consuming biologically active compounds outside the conditions for which they were intended.^3,6,18

There are also unresolved scientific ques­tions specific to plant-made pharmaceuticals themselves. Plant cells can attach sugar mol­ecules called glycans that differ from those produced in the mammalian systems used in traditional vaccine production; these differ­ences may influence protein folding, stability, allergenicity and immune response.^1,3 Protein expression can also fluctuate with environmen­tal conditions, making consistency difficult to guarantee outside of tightly controlled settings. Even when a product appears promising in a laboratory, that does not guarantee its stability, predictability or safety when scaled into agri­cultural production.

As the StarLink and ProdiGene examples illustrate, pharma crops also have economic implications. The entry of a pharmaceutical trait into the food supply has the potential to trigger recalls, export losses, legal disputes and economic damage extending far beyond the original farm. Once trust in the integrity of the food system is compromised, the repercussions can ripple across entire agricultural sectors.¹⁹

At the same time, there is remarkably little transparency surrounding pharma crop develop­ment. Precisely how many pharma crop projects currently exist is difficult to determine. Some research is conducted openly through university partnerships and publicly funded grants, while other projects remain proprietary or occur within private biotechnology companies oper­ating with limited public visibility. Field trial records provide only a partial picture. There is no routine national screening program specifi­cally designed to monitor the food supply for ac­cidental contamination from vaccine-producing crops or other plant-made biologics.

Oversight in the United States is divided among multiple federal agencies. The U.S. Department of Agriculture (USDA) oversees field trials and containment practices,²⁰ while the U.S. Food and Drug Administration (FDA) evaluates product safety and manufacturing standards.²¹ In some situations, the Environmen­tal Protection Agency (EPA) may also become involved. On paper, this framework may appear comprehensive, but in practice, fragmented oversight can create regulatory blind spots— particularly when products exist at the intersec­tion of agriculture, food and medicine.

Public alarm over transparency in the food supply has continued to grow, and some legislators are taking action. In their 2023- 2024 legislative session, Tennessee lawmakers tightened labeling rules “relative to foods that contain certain substances,”²² reflecting rising concern that consumers are too often the last to know when major technological changes are introduced into the foods they eat. As enacted, HB 1894/SB 1903 stated that Tennessee “defines food that contains a vaccine or vaccine material as a drug for purposes of the Tennessee Food, Drug and Cosmetic Act.”²³

At the federal level, Representative Thomas Massie (R-KY) has been one of the more visible congressional voices advocating for stronger labeling protections²⁴ and greater transparency surrounding emerging food technologies.

LESSONS FROM MODERN AGRICULTURE

Americans have already witnessed how dif­ficult it can be to contain agricultural technolo­gies once they are released into open farming systems. Glyphosate, promoted as a targeted so­lution for weed control, has become so pervasive that toxic residues are now routinely detected in soil, water, rainfall, food crops and even the human body. Farmers growing non-GMO or organic crops have repeatedly struggled with chemical drift and cross-contamination from neighboring fields, often suffering economic losses despite never choosing to use the technol­ogy themselves.

Once genetically engineered pharmaceuti­cal traits are released into complex living sys­tems, the unintended consequences will become difficult to predict and hard to reverse. Gene flow, ecological disruption and contamination of conventional crops are not abstract possibilities; they are realities inherent to working with living biological systems that do not respect fences, field lines or regulatory categories.¹⁹

None of this necessarily means that every form of plant-based pharmaceutical research carries the same level of risk or is inherently bad. Some applications developed within tightly controlled systems might eventually prove use­ful for limited and highly specialized medical purposes. However, even advocates of pharma crop technology have long acknowledged a critical point: crops engineered to produce phar­maceutical compounds should have little or no role in the human food or animal feed supply.

Food is fundamentally different from other products, and certainly is unlike prescription medications taken intentionally under medi­cal supervision. Nor is food a manufacturing platform or commercial delivery system. Food is one of the most intimate substances human beings encounter daily. It enters our homes and our own and our children’s bodies. It influences human development beginning in the womb and affects health throughout the lifespan. Food is consumed continuously and by every segment of the population—including infants, pregnant women, the elderly and individuals with under­lying health conditions.

Once the food supply is used to produce pharmaceutical substances, the distinction between nourishment and medication becomes increasingly difficult to define—in ways that deserve far greater public discussion than they have yet received. Pharmaceutical compounds are specifically designed to exert biological activity. The long-term implications of chronic, low-level exposure—whether through acciden­tal contamination, environmental persistence or unintended dietary consumption—are largely unknown. Important questions also remain regarding broader agricultural and ecological consequences—including potential effects on pollinators, soil ecosystems, wildlife and seed integrity—as well as consequences for export markets and public confidence in the food sup­ply.

The central question, therefore, is whether society is prepared to normalize the trans­formation of food crops into pharmaceutical production systems before the long-term bio­logical, ecological, agricultural and economic consequences are fully understood. History has repeatedly shown the risks of prematurely integrating unpredictable technologies into large-scale agricultural infrastructure. At its core, this debate raises broad questions about the future of food itself. Before society moves further down the path of turning agriculture into a platform for pharmaceutical production, the public deserves transparent debate, independent long-term safety research and a full accounting of the potential risks, not only to human health, but also to the integrity and resilience of the food supply upon which everyone depends.

REFERENCES

1. Saxena J, Rawat S. Edible vaccines. In Ravi I, Baunthiyal M, Saxena J (eds.), Advances in Bio­technology. New Delhi: Springer, 2014.
2. Children’s Health Defense Team. The changing face of vaccinology. Children’s Health Defense, Apr. 3, 2018.
3. Stander J, Mbewana S, Meyers AE. Plant-derived human vaccines: recent developments. BioDrugs. 2022 Jul 12;36(5):573-589.
4. McCullough S. Hands Off My Food! How to De­fend Your Food, Health, and Freedom. New York: Skyhorse Publishing, 2026, p. 181.
5. Hiatt A, Cafferkey R, Bowdish K. Production of antibodies in transgenic plants. Nature. 1989 Nov 2;342(6245):76-78.
6. Kurup VM, Thomas S. Edible vaccines: prom­ises and challenges. Mol Biotechnol. 2020 Feb;62(2):79-90.
7. Mar TS, Gomez-Lim MA, Palmer KE. Perspec­tive: edible vaccines—a concept coming of age. Trends Microbiol. 1998 Nov;6(11):449-453.
8. Thanavala Y, Mahoney M, Pal S, et al. Immu­nogenicity in humans of an edible vaccine for hepatitis B. Proc Natl Acad Sci U S A. 2005 Mar 1;102(9):3378-3382.
9. Sala F, Manuela Rigano M, Barbante A, et al. Vaccine antigen production in transgenic plants: strategies, gene constructs and perspectives. Vac­cine. 2003 Jan 30;21(7-8):803-808.
10. Kansteiner F. Mitsubishi Chemical bids adieu to Medicago—and the company’s plant-based CO­VID shot Covifenz. Fierce Pharma, Feb. 3, 2023.
11. Kirby T. Philip Morris ejected from Canadian vaccine collaboration. Lancet Respir Med. 2023 Apr;11(4):e40.
12. Children’s Health Defense Team. Smokin’ new technology to produce flu vaccines. Children’s Health Defense, Feb. 7, 2018.
13. Health Canada. Health Canada authorizes Medi­cago COVID-19 vaccine for adults 18 to 64 years of age. Government of Canada, Feb. 24, 2022. https://www.canada.ca/en/health-canada/news/2022/02/health-canada-authorizes-medicago-covid-19-vaccine-for-adults-18-to-64-years-of-age.html
14. Liu A. GlaxoSmith-Kline, Medicago’s plant-based COVID vaccine, Covifenz, wins first approval. Fierce Pharma, Feb. 24, 2022.
15. BioPharm International Editors. Researchers from the University of California Riverside investigate plant-based mRNA vaccines. BioPharm International, Sep. 17, 2021.
16. Taylor MR, Tick JS. The StarLink case: issues for the future. Pew Initiative on Food and Biotechnology, n.d. https://www.pew.org/-/media/legacy/up­loadedfiles/wwwpewtrustsorg/reports/food_and_biotechnology/hhsbiotech­starcasepdf.pdf
17. Tucker J. The Prodigene incident. In Case Studies in Agricultural Biosecurity, Federation of American Scientists, 2011. https://biosecurity.fas.org/education/dualuse-agriculture/2.-agricultural-biotechnology/prodigene-incident.html
18. U.S. Food and Drug Administration. Guidance for Industry: Drugs, Biologics, and Medical Devices Derived from Bioengineered Plants for Use in Humans and Animals. Draft guidance, FDA-2002-D-0135, Sep. 11, 2002. https://academy.gmp-compliance.org/guidemgr/files/BIOPLANT.PDF
19. Andow D, Daniell H, Gepts P, et al. and Andow D (ed.). A Growing Concern: Protecting the Food Supply in an Era of Pharmaceutical and Industrial Crops. Union of Concerned Scientists, December 2004. https://www.ucs.org/resources/protecting-food-supply-era-pharmaceutical-and-industrial-crops
20. Animal and Plant Health Inspection Service. Release permits for pharmaceu­ticals, industrials, value added proteins for human consumption, or for phy­toremediation. U.S. Department of Agriculture, last modified Feb. 24, 2026. https://www.aphis.usda.gov/biotechnology/release-permits-pharmaceuticals-industrials-value-added-proteins-human-consumption-or?page=1
21. Guidance for Industry: Recommendations for the Early Food Safety Evaluation of New Non-Pesticidal Proteins Produced by New Plant Varieties Intended for Food Use. U.S. Food & Drug Administration, June 2006 (content current as of Oct. 5, 2021). https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-recommendations-early-food-safety-evaluation-new-non-pesticidal-proteins-produced
22. https://legiscan.com/TN/text/HB1894/2023
23. https://wapp.capitol.tn.gov/apps/BillInfo/Default?BillNumber=HB1894&ga=113
24. https://massie.house.gov/news/email/show.aspx?ID=S4GTPSKFBP6BT7UWUOI5AUC6GU

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