GM Purple Tomato to “keep cancer at bay”

Claims

A GM purple tomato was genetically engineered with genes from the snapdragon plant to contain high levels of the antioxidant anthocyanin, a type of polyphenol. The GM tomato was developed by Prof Cathie Martin at the John Innes Centre (JIC) in the UK.((John Innes Centre (2022). Norfolk Plant Sciences welcomes major milestone decision on purple GM tomatoes. 8 Sept. https://www.jic.ac.uk/press-release/norfolk-plant-sciences-welcomes-major-milestone-decision-on-purple-gm-tomatoes/))

From the start, the GM tomato was promoted in the media as a supposedly cancer-fighting food. For example, on 27 October 2008, the UK’s Daily Express headlined its story about the GM tomato’s development, “Purple tomato can beat cancer”. The article added that it “could also keep you slim, ward off diabetes and help to safeguard your eyesight”.((Fletcher V (2008). Purple tomato can beat cancer. Daily Express, 27 Oct. https://www.express.co.uk/news/uk/68047/Purple-tomato-can-beat-cancer))

Reuters headlined its article, “Scientists develop cancer fighting purple tomato”.((Kahn M (2008). Scientists develop cancer fighting purple tomato. Reuters, 26 Oct. https://www.reuters.com/article/idUSTRE49P2KF/)) Like the Express article, the Reuters piece mentioned a small “pilot” feeding study on cancer-prone mice conducted by Cathie Martin and colleagues, which found that the mice fed the GM tomato lived longer than those fed non-GM red tomatoes.((Butelli E et al (2008). Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors. Nature Biotechnology 26: 1301–1308. https://www.nature.com/articles/nbt.1506))

The “cancer fighting purple tomato” claims were not made up by the press, but originated with the media work of the John Innes Centre. The JIC had headed its 26 October 2008 press release, “Purple tomatoes may keep cancer at bay”.((John Innes Centre (2008). Purple tomatoes may keep cancer at bay. 26 Oct. Version archived in Wayback Machine 30 Apr 2009. https://web.archive.org/web/20090430135628/http://www.jic.ac.uk/corporate/media-and-public/current-releases/081026martin.htm))

In a 2023 press release Norfolk Plant Sciences toned down the previous health claims for the product and did not mention cancer.((Norfolk Healthy Produce (2023). Norfolk Plant Sciences’ high antioxidant purple tomato completes FDA consultation. 10 Jul. https://www.norfolkhealthyproduce.com/fda-announcement)) This suggests that some legal caution had entered the marketing strategy for the tomato.

Yet Norfolk Plant Sciences repeatedly uses the word “healthy” to describe the GMO tomato. Indeed, the company has named its US subsidiary, which announced the favourable outcome of the FDA review of the GM purple tomato, Norfolk Healthy Produce. Norfolk Plant Sciences states that Norfolk Healthy Produce “is actively developing and marketing the next generation of innovative vegetables and fruits”.((Norfolk Healthy Produce (2023). Norfolk Plant Sciences’ high antioxidant purple tomato completes FDA consultation. 10 Jul. https://www.norfolkhealthyproduce.com/fda-announcement))

Results

Pushback on claims

The Daily Express and other media following the anti-cancer line were quickly slapped down by the UK’s National Health Service (NHS) and Cancer Research UK (CRUK). According to an article in NHS Choices, reporting the views of the NHS Knowledge Service: “These claims are not actually based on benefits seen in humans, but rather from a small-scale study of mice that were given an extract of genetically modified tomatoes.” The NHS Knowledge Service also noted: “The small sample sizes used mean the results may have occurred by chance. Also until the tomato is tested in humans we cannot be sure that it will offer the same benefits, or that there will not be any unexpected harms.” It concluded that without further research, the claims that these GM tomatoes “can beat cancer” cannot be supported.((NHS Choices (2008). Purple tomatoes “beat cancer”. 27 Oct. Version archived by Wayback Machine 2 May 2009. https://web.archive.org/web/20090502045505/http://www.nhs.uk/news/2008/10October/Pages/Purpletomatoes.aspx))

Cancer Research UK wrote on its Science Update blog that “cancer is a complex disease that has lots of ‘causes’… The problem with a lot of the coverage of the super-tomato story is that it misses out on this complexity… There’s also a big – and in our opinion unwarranted – assumption in some of the coverage. And that’s the simple equation that antioxidants = good. There’s a fair amount of evidence that some antioxidants in our foods can help prevent some kinds of cancer in some people. But the complexity of this evidence often gets translated in the media and in advertising to ‘antioxidants prevent disease’. And that’s not what the science says.” ((Cancer Research UK (2008). Purple tomatoes won’t beat cancer. 27 Oct. Version archived by Wayback Machine 17 Jul 2009. https://web.archive.org/web/20090717012343/http://scienceblog.cancerresearchuk.org/2008/10/27/purple-tomatoes-wont-beat-cancer/))

Antioxidants: The science

In its pushback against the “anti-cancer” claims for the GM tomato, Cancer Research UK points to a New Scientist article on the health effects of antioxidant supplements. The article cites differing and contradictory findings from various studies and concludes that “at best, antioxidant supplements do little or nothing to benefit our health. At worst, they may even have the opposite effect, promoting the very problems they are supposed to stamp out.” ((Melton L (2006). The antioxidant myth: A medical fairy tale. New Scientist, 2 Aug. https://www.newscientist.com/article/mg19125631-500-the-antioxidant-myth-a-medical-fairy-tale/   An archived version of this article is here: https://archive.ph/MxDUJ))

This view is reflected by the findings of a mini-review of the human health effects of a class of antioxidants called polyphenols (which include anthocyanin), as ingested from both food and supplement sources. Authored by scientists from Harvard University and the University of Melbourne, the mini-review emphasises “the need for increased regulation and guidelines for polyphenol consumption and supplementation in order to ensure consumers remain safe and informed about polyphenols”. The scientists point out that supplements taken in pill form may make it easily possible to exceed safe levels, potentially causing serious ailments, such as stroke or increased risk of death.((Cory H et al (2018). The role of polyphenols in human health and food systems: A mini-review. Front Nutr 5: 87. Sep 21. doi: 10.3389/fnut.2018.00087 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6160559/))

Venket Rao, professor emeritus at the University of Toronto’s Dept of Nutritional Sciences, warned of the dangers of overdosing on antioxidants. He said: “We have evidence that antioxidants are good for you, but we also have well-controlled clinical studies showing that at megadoses they could be harmful to you.” ((CBC News (2013). Antioxidant supplement overload can be ‘hazardous’. 28 Aug. https://www.cbc.ca/news/health/antioxidant-supplement-overload-can-be-hazardous-1.1412993))

The GM purple tomato is a food and not a pill supplement. Nonetheless, the high anthocyanin levels in the tomato may present similar risks as those from supplements, as explained below.

Too much of a good thing?

Former US EPA scientist Dr Ray Seidler said:((All quotes from Dr Seidler are from: Robinson C (2024). As GM purple tomato goes on sale to home gardeners in US, dubious cancer claims reappear. GMWatch, 19 Feb. https://www.gmwatch.org/en/106-news/latest-news/20381)) “When consumed in moderation, anti-inflammatory compounds like anthocyanins can have health benefits. But too much of a good thing may not be good. It has been demonstrated that over-consumption of anthocyanins (e.g. when taken as pill supplements) may cause kidney, liver, and thyroid hormone health effects.((Cory H et al (2018). The role of polyphenols in human health and food systems: A mini-review. Front Nutr 5:87. doi: 10.3389/fnut.2018.00087. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6160559/)) Anthocyanins are part of a group of compounds called polyphenols, which may also limit or interfere with iron absorption.” ((Mennen LI et al (2005). Risks and safety of polyphenol consumption. Am J Clin Nutr 81(1 Suppl):326S-329S. doi: 10.1093/ajcn/81.1.326S.  https://pubmed.ncbi.nlm.nih.gov/15640498/))     

Drawing attention to the GM purple tomato’s extremely high anthocyanin levels, Dr Seidler said, “The average American consumes around 12.5 milligrams of anthocyanins per day.((Wu X et al (2006). Concentrations of anthocyanins in common foods in the United States and estimation of normal consumption. J Agric Food Chem 54(11):4069-75. doi: 10.1021/jf060300l. https://pubmed.ncbi.nlm.nih.gov/16719536/)) The anthocyanin content from the GM tomato averages about 500mg per 100g of fresh fruit,((The Silicon Review (2022). USDA approves the genetically modified purple tomatoes. 13 Sept. https://thesiliconreview.com/2022/09/us-regulators-approve-gm-tomatoes ; Norfolk Plant Sciences (2021). Information supporting a regulatory status review of tomato genetically engineered to produce increased levels of anthocyanins. 31 Jul. https://www.aphis.usda.gov/brs/pdf/rsr/21-166-01rsr-review-submission.pdf)) some 40 times more than the daily average consumption. One hundred grams of tomato is less than half a cup. Other naturally purple and red coloured fruits (sweet cherries, blackberries, strawberries, red raspberries, black grapes) contain anthocyanins in the range of 3-143mg/100g,((Healthline (2023). What is anthocyanin? Foods list, benefits, and more. Updated 6 Oct. https://www.healthline.com/nutrition/anthocyanin. Summary is based on data from: Manolescu BN et al (2019). Dietary anthocyanins and stroke: A review of pharmacokinetic and pharmacodynamic studies. Nutrients 11(7):1479. doi: 10.3390/nu11071479. https://pubmed.ncbi.nlm.nih.gov/31261786/)) up to 160-fold less than the GM purple tomato.”

Michael Antoniou, a London-based professor of molecular genetics and toxicology, explained the double-edged role of antioxidants, which can benefit or impair health, depending on the individual and the circumstances.

“The health claims around ingesting high levels of antioxidants such as anthocyanins are based on their ability to neutralise reactive oxygen species (ROS). ROS perform vital health-promoting functions.

“However, ROS can also damage molecules (including DNA) and cells, leading to diseases such as cardiovascular disease and cancer. The key to good cell and organ function is maintaining a balance between producing enough ROS to appropriately modulate vital functions but not so much as to bring about damage and disease.

“Ingesting megadoses of antioxidants, such as anthocyanins from even a modest portion of the GM purple tomatoes, could interfere with the delicate balance between too much and too little ROS, leading to negative health outcomes.

Supporting these views, a systematic review of randomised trials on antioxidants by the Cochrane Library found no evidence that they can reduce risk of mortality in healthy or sick people and concluded that some antioxidants can increase the risk of mortality. The authors concluded, “Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.” ((Bjelakovic G et al (2012). Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database))

This type of in-depth evaluation has not happened with the GM purple tomato, even though it contains higher levels of antioxidants than the levels in the pill supplements that some scientists warn against ingesting.

No evidence of food safety

Prof Antoniou warned that, as the GM tomato has been genetically engineered to change biochemical pathways to produce high amounts of anthocyanin, this could also lead to unintended alterations in the tomato’s composition: “Biochemical pathways are interlinked, so introducing a new core pathway could lead to biochemical changes resulting in the production of novel toxins or allergens.

“And this is the risk from just the intended change. In addition, the GM transformation process (plant tissue culture and plant cell transformation) will inevitably give rise to hundreds or thousands of sites of unintended DNA damage (mutations).((Latham JR et al (2006). The mutational consequences of plant transformation. J Biomed Biotechnol. DOI: 10.1155/JBB/2006/25376. http://www.ncbi.nlm.nih.gov/pubmed/16883050; Wilson AK et al (2006). Transformation-induced mutations in transgenic plants: Analysis and biosafety implications. Biotechnol Genet Eng Rev 23: 209–238. http://www.ncbi.nlm.nih.gov/pubmed/22530509)) These wide scale mutations can change patterns of gene function and altered biochemistry and composition, with unknown health consequences.((Wilson AK et al (2006). Transformation-induced mutations in transgenic plants: Analysis and biosafety implications. Biotechnol Genet Eng Rev 23: 209–238. http://www.ncbi.nlm.nih.gov/pubmed/22530509))

“There is no evidence that the developers of the GM purple tomato have carried out the kind of molecular analyses (proteomics and metabolomics) that could help establish whether they only got the change they want, with no unintended changes. As a result, we don’t know if these tomatoes are safe to eat.”

Antibiotic resistance genes

The GM purple tomato contains an antibiotic resistance marker gene (the so-called nptII gene),((Butelli E et al (2008). Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors. Nature Biotechnology 26: 1301–1308. https://www.nature.com/articles/nbt.1506)) which confers resistance to antibiotics including kanamycin and neomycin. The purpose of these genes in this case is to enable the genetic engineer to check which cells have successfully incorporated the snapdragon genes into their genome.

Controversy has simmered over antibiotic resistance marker genes in GMOs for many years but has never been resolved. The concern is that such genes could transfer to disease-causing bacteria and add to the already serious problem of antibiotic resistance in humans and other animals.

The World Health Organization says, “Although the probability of transfer is low, the use of gene transfer technology that does not involve antibiotic resistance genes is encouraged.” ((World Health Organization (2014). Food, genetically modified. 1 May. https://www.who.int/news-room/questions-and-answers/item/food-genetically-modified))

Norway has banned the use of GM varieties containing antibiotic resistance marker genes.((Myskja BK, Myhr AI (2020). Non-safety assessments of genome-edited organisms: should they be included in regulation? Sci Eng Ethics 26(5):2601–2627. doi: 10.1007/s11948-020-00222-4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7550366/))

In the EU, Directive 2001/18 states, “The issue of antibiotic-resistance genes should be taken into particular consideration when conducting the risk assessment of GMOs containing such genes” and recommends that they are phased out from commercialised GMOs by 2008.((European Parliament and Council (2001). Directive 2001/18/EC of the European Parliament and of the Council of 12 March 2001 on the deliberate release into the environment of genetically modified organisms and repealing Council Directive 90/220/EEC. http://eur-lex.europa.eu/legal-content/en/TXT/?uri=CELEX%3A32001L0018  See Article 4, para 2.)) However, the GMO industry failed to do so.

There appears to be no independent assessment of risks posed by the presence of an antibiotic marker gene in the GM purple tomato.

Regulatory status

In 2022 the US Dept of Agriculture (USDA) deregulated the GM purple tomato,((USDA (2022). APHIS issues first regulatory status review response: Norfolk Plant Sciences’ Purple Tomato. 6 Sept. https://www.aphis.usda.gov/aphis/newsroom/stakeholder-info/sa_by_date/sa-2022/purple-tomato)) effectively removing it from the agency’s regulatory framework. In 2023 the US Food and Drug Administration (FDA) sent the developers a “no questions” letter.((US FDA (2023). Letter to Cathie Martin and Nathan Pumplin, “Re: Biotechnology Notification File No. BNF 00o178”. 20 Jun 2023. https://www.fda.gov/media/170056/download ; see also: ISAAA (2023). GE high antioxidant purple tomato completes FDA consultation. 19 Jul. https://www.isaaa.org/kc/cropbiotechupdate/article/default.asp?ID=20311)) This letter confirms that based on the data supplied by the applicant, the GM tomato “does not raise issues that would require premarket review or approval by FDA”.((US FDA (2023). Letter to Cathie Martin and Nathan Pumplin, “Re: Biotechnology Notification File No. BNF 00o178”. 20 Jun 2023. https://www.fda.gov/media/170056/download))

Commercial launch in the US

Following favourable reviews by the US FDA and USDA, the GM tomato was commercially launched in the US in 2024((The Sainsbury Laboratory (2024). US gardeners rush to snap up purple tomatoes pioneered in Norfolk. 22 Feb. https://www.tsl.ac.uk/news/us-gardeners-rush-to-snap-up-purple-tomatoes-pioneered-in-norfolk)) by Norfolk Plant Sciences and its US subsidiary Norfolk Healthy Produce, under the name “Purple Tomato”.((John Innes Centre (2024). Norfolk Plant Sciences. https://www.jic.ac.uk/research-impact/commercial-and-societal-impact/collaboration-translation/norfolk-plant-sciences/  Accessed 27 Aug 2025 ; Woodruff S (2024). Gardeners can now grow a genetically modified purple tomato made with snapdragon DNA. NPR, 6 Feb. https://www.npr.org/sections/health-shots/2024/02/06/1228868005/purple-tomato-gmo-gardeners)) Seeds were being sold to home gardeners((The Sainsbury Laboratory (2024). US gardeners rush to snap up purple tomatoes pioneered in Norfolk. 22 Feb. https://www.tsl.ac.uk/news/us-gardeners-rush-to-snap-up-purple-tomatoes-pioneered-in-norfolk)) at $20 per pack.((Cupriak A (2024). GM purple tomatoes developed in Norfolk hit US shelves. Farmers Guide, 9 Mar. https://www.farmersguide.co.uk/rural/food-drink/gm-purple-tomatoes-developed-in-norfolk-hit-us-shelves/)) In 2024 the company got its tomatoes into some supermarkets on the East Coast and was targeting high-end restaurants.((Anderson M (2025). Norfolk Healthy Produce’s purple tomatoes coming to Northern California restaurants. Sacramento Business Journal, 10 Jun. https://www.bizjournals.com/sacramento/news/2025/06/10/norfolk-healthy-produce-purple-tomato-restaurants.html))

Conventionally bred purple tomatoes

Heirloom non-GM anthocyanin-rich tomatoes (albeit with lower anthocyanin levels than the GM version((Wilson C (2022). Why I am keen to get my hands on genetically modified purple tomatoes. New Scientist, 12 Oct. https://www.newscientist.com/article/mg25634080-900-why-i-am-keen-to-get-my-hands-on-genetically-modified-purple-tomatoes/))) have long been marketed. Heirloom varieties of purple tomato, such as Black Zebra ((Primerasemillas (2025). Tomato seeds Black Zebra. https://www.amazon.co.uk/Tomato-Seeds-Black-Zebra-Indeterminate/dp/B0CQP97P7V)) and Black Krim,((Hensita (2025). Black Krim Russian heritage heirloom meaty beefsteak tomato seeds. Certified French organic grower. https://tinyurl.com/24ec3trr)) are available to growers.

In addition to heirloom varieties, the “Indigo” family of conventionally bred purple tomatoes were developed by Jim Myers, a plant breeder and professor at Oregon State University, by crossing genes from wild tomatoes with modern varieties.((Woodruff S (2024). Gardeners can now grow a genetically modified purple tomato made with snapdragon DNA. NPR, 6 Feb. https://www.npr.org/sections/health-shots/2024/02/06/1228868005/purple-tomato-gmo-gardeners))

It took Martin and her colleagues at Norfolk Plant Sciences 20 years to successfully genetically engineer the GM tomato.((Woodruff S (2024). Gardeners can now grow a genetically modified purple tomato made with snapdragon DNA. NPR, 6 Feb. https://www.npr.org/sections/health-shots/2024/02/06/1228868005/purple-tomato-gmo-gardeners)) In contrast, Myers’s non-GM Indigo Rose purple tomato took just 10 years to develop and was released in 2011.((Pokorny K (2023). OSU breeding program produced series of purple tomatoes with healthy antioxidants. Oregon State University, 21 Apr. https://news.oregonstate.edu/news/osu-breeding-program-produced-series-purple-tomatoes-healthy-antioxidants)) There are currently more than 50 cultivars of the Indigos being grown and bred throughout the world. Myers said, “There’s just all this diversity in the Indigo market class that has come about through conventional breeding. With the GMO tomato, it’s taken them all this time and more to get one variety out there.” ((Woodruff S (2024). Gardeners can now grow a genetically modified purple tomato made with snapdragon DNA. NPR, 6 Feb. https://www.npr.org/sections/health-shots/2024/02/06/1228868005/purple-tomato-gmo-gardeners)) 

Laws on health and nutrient claims

In the EU, nutrition and health claims made for products are tightly regulated and must be “clear, accurate and based on scientific evidence”.((EU Commission (undated). Nutrition and health claims. https://food.ec.europa.eu/safety/labelling-and-nutrition/nutrition-and-health-claims_en)) The EU regulation has been retained in the post-Brexit UK.((UK Government (2021). Guidance: Nutrition and health claims: guidance to compliance with Regulation (EC) 1924/2006. Updated 10 November 2021. https://www.gov.uk/government/publications/nutrition-and-health-claims-guidance-to-compliance-with-regulation-ec-1924-2006-on-nutrition-and-health-claims-made-on-foods/nutrition-and-health-claims-guidance-to-compliance-with-regulation-ec-19242006#section-5))

In the US, under the Federal Food, Drug, and Cosmetic Act, health claims on foods or dietary supplements must be authorised by the FDA.((Schneeman B (2007). FDA’s review of scientific evidence for health claims. J Nutr. 137(2):493-4. doi: 10.1093/jn/137.2.493. https://pubmed.ncbi.nlm.nih.gov/17237334/)) False or unsubstantiated health claims are in violation of the Federal Food, Drug & Cosmetics Act (FDCA).((Practical Law Commercial Transactions (2019). FDA and FTC warn companies making unsubstantiated health claims about CBD products. https://uk.practicallaw.thomsonreuters.com/w-019-8745?transitionType=Default&contextData=(sc.Default)&firstPage=true)) In order for foods to carry an FDA-authorised health claim, “there must be significant scientific agreement (SSA) among qualified experts that the claim is supported by the totality of publicly available scientific evidence for a substance/disease relationship”.((US FDA (2022). Authorized health claims that meet the Significant Scientific Agreement (SSA) standard. https://www.fda.gov/food/food-labeling-nutrition/authorized-health-claims-meet-significant-scientific-agreement-ssa-standard))

Claims about nutrient content can only be made for nutrients for which there is a Recommended Daily Intake (RDI) in the Code of Federal Regulations (CFR) Title 21((FDA (2008). Small entity compliance guide: Nutrient content claims definition for “high potency” and definition for “antioxidant” for use in nutrient content claims for dietary supplements and conventional foods. Jul. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/small-entity-compliance-guide-nutrient-content-claims-definition-high-potency-and-definition; FDA (2013). A food labelling guide: Guidance for industry. https://www.fda.gov/media/81606/download)) – but there is no RDI for anthocyanin in the Code.((FDA (updated 2023). CFR – Code of Federal Regulations Title 21. Updated 22 Dec. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm))

There is no indication that Norfolk Plant Sciences has attempted to validate any health or nutrient claims for the GM tomato, either with the FDA or any other official body.

Companies

The GM purple tomato was developed and is marketed by Norfolk Plant Sciences and its US subsidiary, Norfolk Healthy Produce. Norfolk Plant Sciences is a spinout company from the John Innes Centre and the Sainsbury Laboratory and was established by Cathie Martin and her John Innes Centre colleague Jonathan Jones.((John Innes Centre (2024). Norfolk Plant Sciences. https://www.jic.ac.uk/research-impact/commercial-and-societal-impact/collaboration-translation/norfolk-plant-sciences/  Accessed 27 Aug 2025.))

Patents

Cathie Martin and her Norfolk Plant Sciences colleague Jonathan Jones hold active and pending patents on methods to genetically engineer plants with higher antioxidant compounds, as well as on the plants made with those methods.((Lens.org patent search results, as of 30 Sept 2024: https://www.lens.org/lens/patent/142-512-246-788-300/frontpage?l=en ; https://www.lens.org/lens/patent/172-128-558-724-105/frontpage?l=en ; https://www.lens.org/lens/patent/158-626-006-481-71X/frontpage?l=en ; https://www.lens.org/lens/patent/155-881-460-075-34X/frontpage?l=en ; https://www.lens.org/lens/patent/088-201-907-785-074/frontpage?l=en ))

Norfolk Plant Sciences targets seed company over alleged patent infringement

In its 2024 catalogue, Baker Creek Heirloom Seed Company in the US offered a “non-GMO purple tomato”, the Purple Galaxy. It even featured on their catalogue’s cover.

On 19 February 2024, Baker Creek said it was contacted by Norfolk Healthy Produce, which “expressed concern that the Purple Galaxy might have been derived from its patented genetically engineered tomato”.((Baker Creek Heirloom Seed Company Facebook post (2024). 19 Feb. https://www.facebook.com/rareseeds/posts/pfbid0k3R5xH5359hqPaP3Vmx6sF8gK3a4Xu4rSCsUw6Cz6J5gE4mqSXoe1bdR29uHsEa2l)) Baker Creek immediately withdrew the Purple Galaxy seeds, saying, “Subsequent laboratory testing conducted in conjunction with Norfolk did not conclusively establish a relationship between the Purple Galaxy and Norfolk’s GM purple tomato. Indeed, such contamination should be unlikely in Europe, given its approach to GM crops. But the testing also did not conclusively establish that the Purple Galaxy is truly free of any genetically modified material.” ((Baker Creek Heirloom Seed Company Facebook post (2024). 19 Feb. https://www.facebook.com/rareseeds/posts/pfbid0k3R5xH5359hqPaP3Vmx6sF8gK3a4Xu4rSCsUw6Cz6J5gE4mqSXoe1bdR29uHsEa2l))

Baker Creek also stated that it “remains steadfast in its commitment to selling only heirloom and open-pollinated, non-Genetically Modified (‘non-GM’) varieties”.((Rare Seeds (2024). FAQ: Baker Creek discontinues Purple Galaxy tomato seeds. https://www.rareseeds.com/faq))

Baker Creek insists that it did its due diligence: “We sourced the seed for the Purple Galaxy from a plant breeder in Europe – where GM tomatoes are not approved – who has collected rare tomato seeds for decades and grows more than 1,000 varieties of tomatoes annually. We actively followed his attempts to breed a purple flesh tomato over the course of three years. In the beginning, using two varieties, he had a fruit that was definitely not purple; it was a purplish red with a few purple streaks. Cultivating five generations over three years, he ultimately had a beautiful tomato with purple skin and flesh. We then travelled to Europe to see the plants for ourselves.” ((Rare Seeds (2024). FAQ: Baker Creek discontinues Purple Galaxy tomato seeds. https://www.rareseeds.com/faq))

However, C.S. Prakash, who runs the pro-GMO AgBioWorld website,((AgBioWorld (2011). About AgBioWorld. Accessed 8 Mar 2025. https://twitter.com/i/lists/1561751668819099648)) accused Baker Creek of lying and deliberately stealing Norfolk Plant Sciences’ patented germplasm. He posted on X: “Liar, liar… your pants on fire! How Bakers Seeds simply swiped some GMO purple tomato seeds from Norfolk Plant Sciences, gave it a fancy name and marketed it as heirloom tomato to its gullible customers!” ((C. S. Prakash X page (2024). https://twitter.com/i/lists/1561751668819099648))

Norfolk Healthy Produce unambiguously said the Purple Galaxy was GMO: “Given its remarkable similarity to our purple tomato, we prompted Baker Creek to investigate their claim that Purple Galaxy was non-GMO. We are told that laboratory testing determined that it is, in fact, bioengineered (GMO). This result supports the fact that the only reported way to produce a purple-fleshed tomato rich in anthocyanin antioxidants is with Norfolk’s patented technology. We appreciate that Baker Creek tested their material, and after discovering it was a GMO, removed it from their website.” ((AgDaily (2024). Seed catalog throws tantrum after listing GMO tomato by accident. 20 Feb 2024. https://www.agdaily.com/news/seed-catalog-throws-tantrum-after-listing-gmo-tomato-by-accident/))

In the absence of either Baker Creek or Norfolk Healthy Produce posting the lab results publicly, it is impossible to know whether they showed the Purple Galaxy was GMO or not.

All we know is that apparently, the testing company didn’t find the obviously GM transgenes (artificially introduced GM genes) they looked for in their first testing – probably the snapdragon genes – but then Norfolk “suggested additional genes to test for”. According to Baker Creek’s post, these results were inconclusive.((Baker Creek Heirloom Seed Company Facebook post (2024). 19 Feb. https://www.facebook.com/rareseeds/posts/pfbid0k3R5xH5359hqPaP3Vmx6sF8gK3a4Xu4rSCsUw6Cz6J5gE4mqSXoe1bdR29uHsEa2l))

So did the testing company find the snapdragon genes, which are responsible for the increased anthocyanin levels? Or did it find genes that may be found in the GM purple tomato but which are naturally occurring? If the latter, they are not patent-protected.((See, for example, two patents covering the GM purple tomato on Lens.org, which cover genes inserted by transgenesis and/or cisgenesis but not genes from conventional breeding; https://www.lens.org/lens/patent/142-512-246-788-300/frontpage?l=en ; https://www.lens.org/lens/patent/172-128-558-724-105/frontpage?l=en)) European law, correctly interpreted, does not allow patents on naturally occurring genes.((No Patents on Seeds! (undated). What is the problem? Accessed 11 Mar 2025. https://www.no-patents-on-seeds.org/en/background/problem)) 

Breeders’ patent fears

Plant breeders are becoming increasingly fearful of inadvertently infringing the patents of seed companies, in particular those of the large multinationals, which have taken to sending threatening letters to the breeders, warning them of the consequences of using their intellectual property.

An article called “Laying claim to nature’s work: Plant patents sow fear among small growers” describes the experience of Adaptive Seeds, an organic seed company. The company was contacted by BASF, the owner of Nunhems, the fourth-largest vegetable breeding company in the world, with a list of varieties of seeds and traits Nunhems had patented. According to the article, “It was an ominous reminder of just how many traits and varieties BASF has control over.”

Adaptive Seeds founder Andrew Still said, “There’s always a general concern that one day they’re going to decide we’re selling something that they think is theirs and they’re going to sue us over that.”

Phil Howard, a professor in the department of community sustainability at Michigan State University, explained that as patent law is complicated and ambiguous, many small-scale breeders don’t know if the seeds they want to work with are patented or not. He said this stifles their freedom to experiment.((Scotten M (2024). ‘Laying claim to nature’s work’: plant patents sow fear among small growers. The Guardian, 25 Jan. https://www.theguardian.com/environment/2024/jan/25/plant-patents-large-companies-intellectual-property-small-breeders))

Author: Claire Robinson. Historical original research and review: Jonathan Matthews. Review and editing: Franziska Achterberg. Scientific review: Dr Ray Seidler; Dr Michael Hansen; Prof Michael Antoniou.