The prevalence of food allergies to mustard appears to be growing, and its uses in agriculture-as well as in the preparation of various foods and food additives-increase the risks of accidental contamination. Insight.
1. Background.
1.1. Mustard, botany and uses
Mustard belongs to the Brassicaceae family. Its most common species are:
– White/yellow mustard(Sinapis alba L.), prized for the aromatic properties of its seeds,
– brown/eastern mustard(Brassica juncea L.), of strong interest both as a spice and for edible oil production,
– black mustard(Brassica nigra L.), used in the food industry to produce oil and in the pharmaceutical industry for poultices.
1.2. Prevalence of food allergies in Europe
EFSA(European Food Safety Authority) was requested by the Food Safety Authority of Ireland (FSAI), in 2011, to perform a scientific review of the prevalence of food allergies in Europe. In the hope of establishing possible tolerance thresholds for each allergen, as well as defining the state of the art on qualitative-quantitative analytical methods. The initial research was commissioned from the University of Portsmouth (UK), which published the outcome in 2013. (1)
The scientific review considered the then-available literature on the prevalence of food allergies in Europe and worldwide. On this basis, EFSA published a scientific opinion in 2014 on immunoglobulin (Ig)E-mediated and non-immunoglobulin (Ig)E-mediated food allergies, celiac disease, and adverse reactions to sulfites in food. (2) Complex work, partly because of the recurrence of studies based on patient statements, which are not confirmed by clinical diagnoses.
2. Mustard allergy
2.1. Prevalence of allergies
EFSA could not assess the trend of mustard allergy expression in the population. In fact, the researchers identified one and only one study on the subject, conducted in France on a sample of subjects aged 5-17 years. Clinical data, such as those on the prevalence of sensitization and those on the incidence of allergic reaction, are very scarce.
France-which continues to be the country with the most data available-reported sensitizations of children and adults in a wide range (1-28%), over the period 1983-2001. This is followed by Spain, where, however, only skin prick testshave been conducted. In Italy, mustard allergy, negligible according to ante-2013 studies, is reportedly on the rise (to an undefined extent) due to the increasing prevalence of sesame consumption and ethnic cuisine.
2.2. Risks and analysis
The risks of adverse reactions and anaphylactic shock appear to be greater in the adult population, although there has been no lack of prick test positivity in children 12-18 months old. Hypothesizing in such cases sensitizations in utero and during lactation. As well as due to possible contamination of baby foods, as already observed for peanuts and sesame.
The dose of protein that triggers allergenic reactions in mustard-sensitive individuals is estimated by EFSA to be about 1 mg. (2) Although reg. EU 1169/11 does not, it should be noted, provide for any tolerance threshold. And it is in any case difficult to apply the EN 15663-1 standard to its seeds because of the limited comparative data available. (3)
2.3. Mustard and allergies, updates
The latest available scientific review (Sharma et al., 2019) shows a significant increase in populations and shares of mustard-sensitized populations. It refers on average to 6-7% of total food allergy cases, with lower incidence in children (1.1% of allergies).
In France, mustard is the fourth most common food allergen, in Spain it is growing, and in Italy a severe allergic reaction has been reported following the consumption of a pizza (cross-contamination). Canada-the second largest global producer of mustard-has been identified as a country at risk. And so is India, its large consumer in all forms (seeds, powder, sauce and oil).
Scientific data on mustard allergy continue to be scarce, limited mostly to the outcomes of skin prick tests.
Evidence of skin reactions and respiratory problems has increased, however, among mustard-allergic individuals, even as a result of inhaling their pollen. (4)
2.4. ‘Hidden mustard’ risk
One real risk that should not be underestimated concerns ‘hidden mustard.’ That is, the presence of mustard in concentrations so low as to be unidentifiable, which can, however, trigger sudden allergic reactions of moderate or even severe severity, depending on individual sensitivity. Concealed mustard may therefore be a cause of immune reactions of unidentified origin (so-called idiopathic anaphylaxis).
Mustard contamination at levels close to the detection threshold may result from its use in foods as a thickener or stabilizer, that is, to impart a ‘pungent touch’ (and allergenicity) to raw materials and food products. And it is necessary to strengthen monitoring, first and foremost in self-monitoring, to ensure proper information to allergic consumers. (4)
2.5. Hidden mustard and other Brassicaceae
A systematic review of prevalence, role and causes of hidden allergen contamination (Taveniers et al., 2014) showed that they underlie 22.4 percent of food allergen reactions. The use of seeds in herbal mixtures is an additional risk factor, which therefore extends to several food categories.
Another risk factor is the structural similarity of some mustard allergens-the 2S reserve proteins, which are very similar among other allergens (e.g., walnut, celery)-to those of other species in the Brassicaceae family. Nevertheless, the specific additional labeling requirement is limited to mustard only. (5)
Therefore, an updated review by EFSA is hoped for, with a view to a possible integration of the list of allergens to be tested in food and mandatory label information (EU reg. 1169/11, Annex II), for the best protection of consumers allergic to the proteins in question.
3. Use of mustard in agriculture
3.1. Use of mustard as a fungicide
ITAB, Institut Technique de l’Agriculture Biologique (ITAB), has obtained approval for a mustard seed powder (from the three species white, oriental, and black) as a fungicide to be applied to caryopses of common wheat, durum wheat, and spelt for protection against certain caries agents. EFSA and member states agreed that there was essentially no, or minimal likelihood of, risk of wheat contamination. (6)
Therefore, mustard seed powder and water can be used, even in organic farming, to protect seeds from fungal attacks. In compliance with the methods of use specifically defined in a special report (SANTE/11309/2017), to be stated in the labeling and technical data sheet of the organic plant protection product. (7)
3.2. Use of mustard in green manure
The ability of mustard to impart structure and organic matter to the soil-as well as to counteract the development of pathogens, nematodes and weeds-has encouraged the use of white mustard and oriental mustard for green manure (cultivation for the purpose of burial in the soil), in the U.S., especially in potato fields. Its efficacy is largely attributed to the glucosinolates it contains, which are capable of biofumigant action. (8)
In Veneto, white and brown mustard, experimented as green manure in preparation for various spring crops, demonstrated nematicidal and biofumigant properties, respectively. Mustard has also proven to be the best crop, among the Brassicaceae, for incorporating phosphorus, nitrogen and potassium. (9)
3.2.1. Mustard green manure green manure, the approaches
Mustard green man ure has also been performed, before potatoes and wheat, in the Best4Soil project in Horizon 2020, where Italy participates through the Plant Production Research Center (CRPV) in Cesena. With the goal of ensuring high productivity over the long term, thanks in part to the containment of diseases and nematodes. (10)
The approaches immediately following mustard green manure are mainly flax and potato. Other crops, cereal and horticultural crops, however, are recommended in rotation for the following year. (11)
3.3. Consociation of mustard with other plants
Mustard intercropping has been tried on numerous crops-banana, flax, beans, chickpeas, cilantro, oats, peas, lentils, wheat, etc. – and has proven to be very useful in combating aphid infestations. (12)
The use of mustard in intercropping has also proven to be very effective in ensuring better production of legumes, with particular regard to chickpeas and peas (13,14).
3.4. Use as a phytodepurator
The eastern mustard variety has been shown to have potential to remove residues of heavy metals, antibiotics and antibiotic-resistance genes from the portion of soil bordering the rhizosphere.
These effects are attributed to mustard’s ability to promote the development of a community of rhizobacteria that can exert purification, especially from antibiotics. (15)
3.5. Invigorating action
In organic farming, Ministerial Decree 18.7.18 no. 6793 allowed the use as a corroborating substance of unrefined mustard oil (obtained exclusively by mechanical pressing, subsequent filtration and dilution in water, with only the possible addition of Tween 80 as an emulsifier). Identical methods of use can be followed in so-called ‘integrated agriculture’ (16,17).
3.6. Mustard in integrated production specifications
Several specifications-in the context of the so-calledSQNPI (National Quality System Integrated Production)-cover the use of mustard in agriculture, in different formulations. A couple of examples:
– The Abruzzo Region recommends the use of oriental mustard for green manure before strawberry and vegetable crops destined for IV Gamma, because of its partial soil disinfection properties, (18)
– Emilia-Romagna indicates the use of nematode-resistant mustard varieties in precession or succession to sugar and seed beets. In addition to mustard oil as a corroborant, (19)
– the use of mustard as a green manure crop is also indicated in private production specifications. Examples include the Virgo collective brand productions, where its use is recommended as an intercrop, prior to renewal crops or spring sowing of cereals. (20)
Conclusions
Exact estimation of the prevalence of mustard allergies is still difficult with data still scarce. The main data available concern the results of skin prick tests and a few double-blind versus placebo tests, essentially limited to the main consuming countries (France, Spain, Canada, India, Finland). The main species involved seem to be white mustard and oriental mustard (black mustard seems to be excluded).
An important risk is the presence of ‘hidden mustard’ – difficult to detect and not indicated on the label – in many foods and preparations, which could also be a cause of idiopathic (i.e., not attributed to a specific event) anaphylaxis. The use of different species of mustard is, moreover, becoming more widespread in agriculture as a green manure crop (burial in the soil). And the possibility of allergenic contamination of agricultural produce following it has been affirmed.
The crops mainly affected appear to be potatoes, sugar (and seed) beets, wheat and other cereal crops, IV Gamma, and strawberries. Since the proteins resist the various processes and heat treatments, operators are advised to be extremely careful in order to avoid omitting the necessary information to allergic consumers in case of cross-contamination.
Dario Dongo and Andrea Adelmo Della Penna
Notes
(1) University of Portsmouth (2013). Literature searches and reviews related to the prevalence of food allergy in Europe. EFSA supporting publication EN-506. https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/sp.efsa.2013.EN-506
(2) EFSA NDA Panel (2014). Scientific opinion on the evaluation of allergenic foods and food ingredients for labelling purposes. EFSA Journal 12(11):3894, https://doi.org/10.2903/j.efsa.2014.3894
(3) Ministry of Health (2014). Food allergies and consumer safety – Guidance document and state of the art. DGISAN Office V, https://www.salute.gov.it/imgs/C_17_pubblicazioni_2134_allegato.pdf
(4) Sharma et al. (2019). A Comprehensive Review on Mustard-Induced Allergy and Implications for Human Health. Clinic. Rev. Allerg. Immunol. 57:39-54, https://doi.org/10.1007/s12016-017-8651-2
(5) Taveniers et al. (2014). Species-specific PCR method for the detection of mustard species (Sinapis alba, Brassica nigra, Brassica juncea) as potential “hidden” allergens in foods. Labinfo 12, https://www.favv-afsca.be/laboratories/labinfo/_documents/2014-07_labinfo12-p23_en.pdf
(6) EFSA (2017). Outcome of the consultation with Member States and EFSA on the basic substance application for mustard seeds powder from Sinapis alba (Brassica alba), Brassica juncea and Brassica nigra for use in plant protection as fungicide. EFSA Supporting Publication EN-1169, https://doi.org/10.2903/sp.efsa.2017.EN-1169
(7) Reg. EU 2017/2066, Approving mustard seed powder as a basic substance in accordance with Regulation (EC) No. 1107/2009. EUR-Lex, https://bit.ly/2XDTeb7
(8) Andrew McGuire (2016). Mustard green manures. Washington State University Extension Bulletin EB1952E:FS219E, https://bit.ly/39jd1in
(9) Veneto Agricoltura (2008). Spring green manure crops. 2007 experimental results in the agricultural sector. VA Sector Experimental Centers, https://bit.ly/2VVgL6B
(10) Best4Soil (2020). Crop rotation: practical information. https://www.best4soil.eu/assets/factsheets/it/12.pdf
(11) Fiorella Pond (2018). Management of cultural techniques to implement soil fertility in organic citrus groves. Social Farming 2.0, https://bit.ly/2XuTokP
(12) Sarker et al. (2007). Effect of intercropping of mustard with onion and garlic on aphid population and yield. J. Bio.-Sci. 15:35-40, https://doi.org/10.3329/jbs.v15i0.2200
(13) Singh et al. (2019). Performance of Chickpea-Mustard Intercropping on Yield and Economics of Chickpea and Mustard Crop under Different Fertility Management and Various Row Combinations. International Journal of Current Microbiology and Applied Sciences 8(1):236-249, https://doi.org/10.20546/ijcmas.2019.801.027
(14) Chapagain et al. (2018). Intercropping of maize, millet, mustard, wheat and ginger increased land productivity and potential economic returns for smallholder terrace farmers in Nepal. Field Crops Research 227:91-101, https://doi.org/10.1016/j.fcr.2018.07.016
(15) Cui et al. (2021) Ryegrass (Lolium multiflorum L.) and Indian mustard (Brassica juncea L.) intercropping can improve the phytoremediation of antibiotics and antibiotic resistance genes but not heavy metals. Science of the Total Environment 784:147093, https://doi.org/10.1016/j.scitotenv.2021.147093
(16) CCPB (2020). Organic Production Standards. Edition 2/2014 Rev. 5, https://bit.ly/3zt0Mdw
(17) SQNPI (2020). National Integrated Production Guidelines 2021 For the drafting of the regional specifications/agronomic techniques section mentioned in Section 12.2.2 of the document: SQNPI – Accession, Management, Control/2021. Rev. 5, https://bit.ly/3nPBB2E
(18) Abruzzo Region (2021). Integrated production regulations 2021 – Agronomic techniques. Department of Agriculture, https://bit.ly/3AstkVM
(19) Emilia-Romagna Region (2021). Integrated production regulations – General rules. Directorate General for Agriculture, Hunting and Fisheries, https://bit.ly/3Cwo4B4
(20) Virgo Wheat (2012). Specifications for production, processing and marketing of Virgo brand products. https://bit.ly/3Cqpr4s
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
Graduated in Food Technologies and Biotechnologies, qualified food technologist, he follows the research and development area. With particular regard to European research projects (in Horizon 2020, PRIMA) where the FARE division of WIISE Srl, a benefit company, participates.
