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We are not yet at risk of finding fake tomatoes or spinach on our supermarket shelves, thank goodness. Though, if the writers are honest, we didn’t know about fake eggs or grapes (from the introduction) prior to doing research for this book, so who knows what might be possible with the right ingredients! Yet we still find fraud among our wholesome fruit, vegetables and grains.
In 2015, boxes of mandarins were found in a Chinese wholesale market. In clear, bold green lettering across the side of the box it said ‘AUSTRALIA’, and then below, in smaller lettering, ‘sweet fruit’. The image on the side of the box was of a muted, somewhat out-of-focus grassland. And in the foreground, perfectly in focus, two juvenile ... lions? What lions have to do with oranges or Australia is unclear and it is for this reason the boxes were investigated. They were, of course, a product of China.
This was just one of many examples of Chinese citrus being rebranded as Australian citrus because the Australian products are more expensive. The imported oranges carry a premium largely because they are viewed as ‘clean’ fruit. Between 2010 and 2012, numerous stories came out that a number of domestic oranges were being sold in China that had had their peel rubbed in carcinogenic Sudan Red dye to make them appear riper than they actually were. The fruit had been picked early in order to get a jump on competitors ahead of the domestic citrus season. It was either artificially matured or dyed to look ripe and sold as US or Australian produce. Because, of course, Asian fruit wasn’t in season yet and consumers knew that. While the dye didn’t appear to affect the flesh, there is obviously a strong likelihood that the dye can be inadvertently ingested during the process of peeling the fruit. No fancy test was necessary as the dye simply rubbed off in your hand or, preferably, on a cloth or tissue. Once the scandal broke all was revealed and consumers lost confidence in their domestic citrus fruits.
Perhaps as a result of the citrus scandals, Australia’s exports to China have been on a steady increase; their citrus exports are currently valued at around £19.3 million (US$30 million). Yet Australian producers are wary, as they obviously don’t want to see their packaging being replicated for the purposes of deceiving customers into thinking that they’re buying Australian when they are not. This is further complicated by the fact that some of this misleading produce is being sold on to other Asian countries. It is tarnishing the Australian brand.
In 2014, Hong Kong had its first suspicious citrus scandal when 5,200 oranges that had been given fake Sunkist brand labels were found on market stalls in Yuen Long. As well as the oranges, the authorities seized over 100,000 forged Sunkist labels. The fakes were uncovered when a customer noticed that the fruit didn’t taste the same and that the peel was thicker than normal. The complaint led to a two-week investigation that culminated in the arrest of the owner of the stalls along with three sales staff.
Fruits and vegetables, in their whole form, generally do not make an appearance in the food fraud databases. Squeeze the oil or juice out of them and it’s fair game, but it would be rather bold to try and dye a parsnip orange and sell it as a carrot. Yet as we saw with the citrus example, there are ways we can still be deceived by the fruit and vegetables we buy – whether it’s how fresh they are, where they’ve come from or how they were produced.
The preservation principle
As anyone who has ever had the privilege of growing their own fruits and vegetables knows, there are natural gluts and lulls in the growing period. You can be desperate for anything that’s not a root vegetable during the winter months and buried beneath more berries than you know what to do with during the summer. It is, therefore, common sense to find ways to preserve things so that you can extend the season in which the garden’s bounty can be enjoyed. Food science has helped us do this.
While many of these methods keep the fruit or vegetable relatively intact – blanching and freezing, or pickling, for example – others turn it into less recognisable products, and this is where the fraudsters have some operating room. Purees, for example, which can be frozen or canned (often for baby food), have been prone to some species swapping and blending. Apricot puree has been substituted for pumpkin puree, apples and plums have been worked into raspberry purees and the purees of cheaper fruits have made their way into more expensive jams. The purees may be an end product themselves, but more often than not they are used in other products such as pudding, yogurt, ice cream and baked goods. In this way the fraud gets passed along the food chain.
To detect these adulterations a number of methods have been used. PCR has been used to differentiate the species in a puree sample based on the DNA present. Chromatography techniques have also been used to identify signature compounds that are unique to particular plant species as a way of identifying what’s in the macerated mixture.
Of course, we are not just faced with trying to preserve our fruits and vegetables for leaner times. In this global food network we have created, we must also find ways of transporting these (often) soft and fleshy products thousands of miles with as little spoilage as possible. To do this, many fruits and vegetables are picked before they are ripe. This is fine for certain groups of plants, known as climacteric plants, because they continue to ripen even once they are picked. These plants produce a lot of ethylene and undergo rapid respiration as they ripen; examples include apples, avocados, apricots, bananas, mangoes, peaches and tomatoes. Non-climacteric plants, as you would expect, do not continue to ripen once they are picked and these include bell peppers, cherries, citrus fruits, cucumbers, grapes, strawberries and pineapples. When was the last time you saw a pineapple that wasn’t green in a UK supermarket?
This basic difference in plant physiology can be used to the advantage of the food industry. Bananas, for example, which would have very little tolerance for being shipped about when perfectly ripe, are instead picked hard and green and stored mature but unripe. When they are needed, the bananas are ripened in a room with ethylene pumped into it, which speeds up the ripening process. Ethylene can also be used to de-green non-climacteric fruits, such as citrus. It will change the colour of the peel from green to orange or yellow so that the fruit appears ripe, but unlike the effect on bananas, it won’t actually help the fruit to ripen. Generally, non-climacteric fruits have to be picked as ripe as possible and then refrigeration or other methods must be used to slow the rotting process.
It is here, in this attempt to slow the decay of our fruit and veg, that we can sometimes be deceived. The most heinous example of this comes from Bangladesh. In 2014, the Bangladesh government started to crack down on the illegal use of formalin in preserving fruit. Formalin is formaldehyde gas dissolved in water and is well known as the substance used to preserve human bodies as well as biological specimens. However, formaldehyde is also found naturally as it is an organic compound produced as a consequence of biological processes. Humans produce it, as do fruiting plants. But the Bangladesh authorities were measuring formaldehyde levels to more than 1,500 times the natural levels found in fruits. Mangoes, for example, were being picked and sprayed with formalin to keep them fresh prior to shipment. When traders received the mangoes, they were getting rid of any that hadn’t survived the journey and then spraying the rest of the mangoes again with formalin before sending them off to retailers. Sometimes retailers were giving the mangoes a third spray of formalin before displaying them on their shelves.
Inhaling formaldehyde can cause irritation of the respiratory system and the eyes as well as nausea, dizziness and headaches. Long-term exposure to formaldehyde has been linked with some forms of cancer. The effects of consuming formalin are less well known, though as it occurs naturally we are eating it as part of our daily diet already. WHO has set the tolerable daily intake level for formaldehyde at 0.15mg/kg per day. This means that a 70kg (154lb) individual shouldn’t consume more than 10.5mg (0.37oz) of formaldehyde daily. Some of the mangoes in Bangladesh were measured as having 46 parts per million (ppm) formaldehyde, so it would take more than one mango (around 250g (8.8oz) of mango flesh) for that person to reach this limit.
The use of formalin is, of course, illegal and if perpetrators are found guilty of using it, they can receive a maximum sentence of life in prison. Yet it is still used. Luckily, it is one of the easier types of fraud to detect. A hand-held device can be purchased for anywhere from £30 to £300 (US$46 to US$467), which will give a reading, no doubt with varying degrees of accuracy, of the amount of formaldehyde in the air. However, there are also formaldehyde dip detectors that are perhaps more accurate for determining formaldehyde concentrations in liquids and solids. These are little strips of paper that simply need to be held to the product being tested. The indicator paper will change colour and this can be compared with a reference chart to give a value in ppm. It’s very similar to a pH test. Thirty strips can be bought online for around £40 (US$65) and this is as straightforward as tests come.
While the use of formalin is clearly an illegal practice, there are methods of preservation that are perfectly legal within the food industry, but perhaps no less deceitful. There are patented formulations that are classified as processing aids, which can help inhibit the oxidation of fruit and vegetables. All of us have used such methods to some extent – we have sprinkled some lemon juice on apple slices to stop them going brown or kept carrot sticks in water for the same purpose. These patented processing aids, which may be no less natural in their origins than some lemon juice, can prevent a cut-up apple from turning brown for approximately 21 days. They do not need to be disclosed on any food label because they are considered a processing aid rather than an ingredient. They don’t pose any health risk as formalin does, but something seems deceitful about it, perhaps because most of us (ourselves included prior to writing this book) aren’t aware that there are methods to keep an apple from turning brown for that long. As a result, we make an assumption that the sliced apple is reasonably freshly packaged – perhaps within a day or two. And this is where food processing begins to blur the lines between what is real and what isn’t.
Over the last decade, the use of nanoparticles in food has been a hot research area, particularly for preservation. We’re not talking about food packaging here, we mean in our food. Silver nanoparticles, for example, have antimicrobial properties and are used in many products where one might not want microbial growth – our underpants for instance. Silver nanoparticles have therefore been used as pesticides but are also being used in coatings for fruit and vegetables to preserve their freshness. Asparagus spears, for example, can be kept in good quality for up to 25 days in cold storage when coated with silver nanoparticles, compared with only 15 days when not. Studies have shown that even after repeated washing, the silver nanoparticles are still found on the skin of some products and, owing to their size, can penetrate the skin and enter the flesh.1
The impact of eating these nanomaterials is unclear and it is a hotly debated topic. Nanoparticles are small enough to pass through cell membranes and the science about how these nanoparticles spread out in a living body and accumulate in different tissues is just starting to unfold. Nanoparticles can also cross the placental barrier, raising concerns about how they may affect the development of an unborn baby. Even as short-term studies are being published, it’s too early to understand any long-term effects of the chronic consumption of nanoparticles. There are clearly advantageous applications of nanotechnology in the food industry. Nano-sized salt, for instance, is one-thousandth the size of a normal grain of salt, but with one million times the surface area. This means far less is required to get the same level of seasoning, which is ideal for reducing salt intake. However, the science on the impact of nanomaterials in our food needs to catch up with the applications.
In the US, the use of nanoparticles in food is subject to the same regulations as adding any other ingredient to food. However, at the moment, the US does not require nano-sized ingredients to be labelled. While the EU does require any nano-sized ingredients to be labelled as such on the packaging, it doesn’t require any nanomaterials used in processing to be declared on the label. So, does a silver nanoparticle coating that migrates into the flesh of a fruit count as a process or an ingredient? This is clearly a grey area. In the meantime, there is a flurry of research to develop the best methods for detecting and quantifying nanoparticles in food.
The differentiation of processing methods and ingredients is an important one. There are 6,000 food additives, including flavourings, glazing agents and improvers, which are used in the behind-the-scenes processing of our food. Remember the CGI analogy from the introduction? These processing methods can convert an immature cheese into a mature cheese in 72 hours. The consumer is under the illusion that they are getting a wedge from a round of a carefully aged cheese – a cave-aged cheddar perhaps – when in fact it’s a stunt cheese disguised by some fancy processing effects. What goes on behind the scenes legally and what is omitted from the label is a topic for many more books. Felicity Lawrence’s Not on the Label and Joanna Blythman’s Swallow This both cover these topics extensively.
But does this constitute food fraud? The EU has yet to develop an official definition of food fraud, but a definition from the US includes ‘the deliberate and intentional substitution, addition, tampering, or misrepresentation of food, food ingredients, or food packaging; or false or misleading statements made about a product, for economic gain’.2 Whether a sliced apple that’s 21 days old and white as the day it was cut is a misrepresentation of food will require expert interpretation of existing food laws. In our non-expert opinion, it feels as though not all the information is being disclosed and it therefore has an air of dishonesty about it.
On the origin of veggies
As we saw with the Asian citrus fruits being sold as a product of Australia, making claims about where fruits and vegetables originate is one of the ways fraudsters can make a little extra money. Tropea red onion (Allium cepa var. Tropea), for example, may look like a normal (albeit slightly elongated) red onion to most consumers. Yet it is a highly prized variety that is cultivated in a very small area in Calabria, a region of southern Italy. Owing to the reputation of the onions grown in this region, this variety was awarded protected geographical indication (PGI) certification under the name ‘Cipolla Rossa di Tropea Calabria’ by the EU in 2008. While the designation gives consumers assurance about the origin and quality of the onion, it also gives fraudsters an opportunity to cash in on a premium product. In 2008, it was estimated that just over 18,000 tonnes of these red onions were produced in the region, yet just over 90,000 tonnes of onions labelled under this PGI brand were sold. As we have seen in previous examples, the numbers simply don’t add up.
To try to protect the PGI designation, researchers began working on some simple tests that could be performed to authenticate the Tropea onions. A group from Italy used mass spectrometry to determine the concentration of 25 different elements in samples from the Tropea region as well as samples grown in nearby regions that are not included in the PGI designation.3 With these elements they were able to build a multi-element profile that could then be statistically analysed to determine which elements were most useful in differentiating the origins of the onions. As it turned out, lanthanides, which are metallic chemical elements commonly referred to as rare earth metals, alkali metals (such as rubidium) and alkaline earth metals (such as strontium and calcium) were the most important elements in distinguishing the geographical origins of these onions. Dysprosium is a rare earth element that is particularly helpful in differentiating the origins of these onions, though it hadn’t been considered in previous onion authentication studies. Onions are particularly efficient in taking up metals from soil, so it is not surprising that the metallic elements feature so prominently in distinguishing what soils they come from.
Faking the country of origin for a foodstuff may not simply be about gaining a premium price for specialised items from very specific regions, such as Tropea onions. More and more consumers are concerned about where their food comes from because they want to support local farmers, they want to minimise the miles their food has travelled or they want to avoid food that has come from regions known to have weaker production standards, maybe even a history of food fraud. Lying about where the food comes from helps to move it in a market that otherwise may not have bought it. For example, in 2014, executives of a family-based vegetable grower in Ontario, Canada, were caught mislabelling produce. They were charged with selling more than CA$1,000,000 (£493,000) worth of vegetables that were not grown on their 400 acres (160 hectares) of greenhouse vegetable-producing land, nor anywhere else in Canada as they were labelled. They were mostly Mexican vegetables. They sold the produce on to major Canadian supermarkets where customers no doubt felt good about buying a Canadian product. The case went to pre-trial stage in January 2015 and hasn’t yet concluded at the time of writing this book.
European regulations to protect the reputation of products from certain geographical origins are a very helpful framework for protecting consumers. The Tropea onions have PGI designation, as we mentioned. Other products, such as prosciutto di Parma from Italy and many wines, have protected designation of origin (PDO), and other foodstuffs have traditional specialities guaranteed (TSG) designation, such as Italian mozzarella. As of 2008, there are 172 fruits, vegetables and cereals that have either PDO or PGI designation, which is about 4 per cent of all products with these origin designations. Some of these include strawberries from the French city of Nîmes, forced rhubarb from Yorkshire, England and chestnuts from Terra Fria, Portugal. The system is not dissimilar to the rules of the old guilds in that the designation carries a particular reputation; the producers will be keen to guard that reputation and have the legal framework to do so.
Before it gets to the consumer, there are advantages in falsifying the country of origin to get around certain import taxes or import bans (as we saw with fish). It can help avoid food safety testing that is conducted more rigorously on imports from certain countries as well. In 2012, EU member states, plus Norway and Iceland, collected 6,472 food samples from countries that are subject to stricter import controls. Of these, 7.5 per cent of the samples exceeded the legal limit for one or more pesticide residues, compared with 1.4 per cent of samples originating from European countries. Within certain countries, the percentage of samples exceeding maximum residue levels (MRLs) was quite high. Over 38 per cent of food samples originating from Malaysia exceeded MRLs; Cambodia, Vietnam and Kenya all exceeded 20 per cent; and India and China both had just under 20 per cent of their samples exceeding MRLs. Products that most frequently exceeded the legal limits included basil (44.3 per cent of samples), okra (27 per cent), grapefruit (17.9 per cent) and celery leaves (17.3 per cent).4
Not only might the pesticide residues exceed legal limits, but in some countries residues of banned pesticides are making an appearance in food. More than 40 per cent of foods tested in Bangladesh contain banned pesticides. Random testing in India in 2013 found banned pesticides in food, often in quantities more than a thousand times the legal limit. Vegetables like cabbage and cauliflower are being dipped in pesticides to keep them fresh while apples and oranges are coated in wax made with the chemicals to extend their shelf life. Levels of the organochlorine heptachlor were 860 per cent above the legal limits for aubergines (eggplants) in India. Rice tested had levels of the insecticide chlorfenvinphos, which is banned in the EU and US because of its toxic effects, 1,324 per cent above the legal limit. Food from countries with less rigorous pesticide regulations is subject to increased monitoring and if the country of origin is false it may escape testing. This is where this kind of fraud starts to become a human health concern.
There are different analytical methods for authenticating food origins and we have seen some of these already. The Tropea onions used trace and rare earth element analysis, which can be done using a number of different techniques. With honey and meat, multi-isotope ratio analysis was conducted and compared with known isoscapes. Combining elemental and isotope analyses seems to provide the most impressive results in determining food origins and as more work is done in this field, traceability of our foodstuffs will become more reliable.
Production perjuries
The way fraudsters stand to make the biggest financial gain on fruits and vegetables is by falsely labelling products as organically produced. Consumers are willing to pay up to twice the price for organic produce. The market demand for organically produced food in 2011 was estimated at £40 billion (US$62.8 billion), triple its 2002 value. The US is the biggest consumer of organic food.
So far, most scandals regarding the mislabelling of organically produced food have revolved around poultry – both the meat and the eggs. These cases have generally been brought to light as a result of whistleblowers rather than any form of routine analysis. Cases regarding mislabelled fruit and vegetables, however, are hard to find in the literature. Whether this is because they don’t exist or because authorities are looking in the wrong places is, as yet, unclear. However, it hasn’t stopped scientists from finding ways of authenticating organically produced food.
Metabolomics has been used to differentiate some organic ingredients from non-organic as there has been some evidence that the different cultivation methods affect the quantities of metabolites, such as antioxidants, in the plants. This approach was used to distinguish ketchup made from organically grown tomatoes from conventional ketchup, for example.5 The researchers from Spain used different techniques in mass spectrometry to separate the different metabolite compounds in the two types of ketchup. They found that antioxidants, such as caffeic acid, were found in significantly higher levels in the organic ketchup compared with the conventional. In fact, overall organic ketchup had higher concentrations of phenolic compounds, which are secondary metabolites in plants that are generally associated with higher nutritional value. However, the utility of this method over the long term is questionable because of that ever-present challenge of natural variability. These chemical signatures can evolve between different production years and depending on the varieties and origins of the tomatoes used.
Perhaps targeting differences in the production methods themselves is more effective. Each country and indeed each organic certification label has its own standards and criteria for organic production. In the EU, one of the requirements of organic farming is that no synthetic pesticides or synthetic mineral fertilisers can be used. In terms of analysis, this is a good starting point for differentiating organically produced fruit and veg from conventional production.
In 2007, scientists from the FSA and University of East Anglia (England) used nitrogen isotopes to try and differentiate organically grown tomatoes, lettuces and carrots from those that were conventionally grown.6 The nitrogen in synthetic fertilisers comes from atmospheric nitrogen and as little fractionation happens in the manufacturing of these fertilisers, the stable isotope ratio of the fertilisers is very close to that of atmospheric nitrogen. Fertilisers used in organic production, however, have usually been through the food chain. As the ratio of 15N to 14N tends to increase with each trophic level, this means that the nitrogen isotope ratio of organic fertilisers is much higher than that of atmospheric nitrogen. When the researchers tested tomatoes, they found that although organically grown tomatoes did have a higher nitrogen isotope ratio, there was enough overlap between the lower values of organically grown tomatoes and the higher values of conventionally grown tomatoes to be ambiguous. There was even more overlap with lettuces and there was almost complete overlap when it came to the carrots. Carrots have a much lower nitrogen requirement than either tomatoes or lettuces and are more often cultivated in open fields rather than polytunnels or greenhouses, which may explain this difference. The conclusion was that nitrogen isotope ratios may provide supporting evidence in an authenticity case, but could not be considered conclusive evidence and were limited in their utility depending on the crop type. A different test was needed.
Figure 9.1. Tracing nitrogen isotopes through conventional and organic farming practices.
In 2014, German scientists tested the suitability of using 1H NMR to build chemical profiles for organic and conventionally grown tomatoes.7 The spectra showed significant differences between the two production methods for two cultivars of tomato. The results are promising, but limited. As we’ve mentioned previously, having a database of chemical signatures of different varieties of tomato cultivated using different farming practices and from different regions of the world is critical to understanding the natural variability – the NMR landscape for tomatoes, if you will. Further studies will have to be conducted as well to determine whether the analysis can be applied to other fruits and vegetables.
For now, it would appear that the authenticity of organic food still very much relies on the enforcement of strict production standards through rigorous certification processes and site inspections. In other words, a lot of paperwork.
Pulses, grains and seedy transactions
We decided to add pulses, grains and cereals to this chapter because, quite frankly, they didn’t fit anywhere else and there is fraud happening in even these most basic of foodstuffs.
Rice appears on the food fraud databases as both an adulterated food and an adulterant of food. Ground into powder, rice has been used to adulterate spices, milk, wine and meat products. However, it has had its fair share of being on the receiving end of fraud as well. In 2011 headlines in Asia claimed that fake rice was being mass-produced in China. The rice was a mixture of potato starch and plastic resin. However, either the authorities covered up the scandal well or it could never be verified because it didn’t go beyond a few headlines. Most rice fraud, however, has to do with the mislabelling or substitution of cheaper varieties as more expensive varieties, mainly basmati. In 2014, a joint effort by Interpol and Europol resulted in the seizure of 1,200 tonnes of counterfeit food, which included 22 tonnes of standard long-grain rice that was claiming to be basmati. Basmati can sell for two to three times the price of other long-grain rice. As well as this premium price on the shelves, brown basmati has no import duty in the UK, whereas other types of rice carry import costs of around £105 (US$164) per tonne. The UK will tolerate as much as 7 per cent non-basmati rice in a bag labelled as basmati, but beyond that it’s considered intentional and fraudulent. DNA markers are used to detect and quantify adulteration of basmati.
In India, pulses (peas and lentils) have been found dyed with synthetic colours and toxic compounds such as lead chromate and metanil yellow. These dyes can be detected using chemical methods that Accum would have used in his time: adding hydrochloric acid will indicate the presence of both lead chromate and metanil yellow. In addition to pulses being dyed, seeds from common vetch (Vicia sativa L.) have been substituted for the split red lentil (Lens culinaris L.). HPLC has been used to look for chemical markers in vetch that aren’t found in the red lentil, β-cyanoalanine and γ-glutamyl-β-cyanoalanine, to detect this adulteration.
As with any other food product, grains, pulses and seeds are more prone to fraud when they are processed beyond anything other than the raw commodity. A perfect example of this is grinding corn, chickpeas, wheat, soy, rice and other cereals and grains down into flour. As we mentioned in Chapter 6, the Chinese milk melamine scandal was preceded by the discovery of melamine in pet food in the US. Evidence suggests that the source of the melamine in the pet food was contaminated wheat gluten. After this scandal, the CFIA’s Food Safety Division devised a list of odourless, colourless, tasteless and commercially available high-nitrogen compounds that could similarly be used to fraudulently increase the protein content of protein-containing foods, including a number of compounds used in fertilisers, such as urea. Scientists from the US FDA quickly devised methods to detect six compounds that they deemed most likely to be used as adulterants. They used a combination of chromatography (separation) and mass spectrometry (amount and type of chemical) techniques to detect the compounds in soy protein, wheat flour, wheat gluten and corn gluten. It’s an example of the science of detection staying one step ahead of the fraudsters.
Of course, less sophisticated adulterants have also made their way into different flours, with the most popular being chalk powder. Substitutions of cheaper flours for more expensive flours also happen – wheat for spelt, for example. There are potential health consequences of such substitutions as people with intolerances, allergies or coeliac disease may be eating wheat flour inadvertently.
Rotten apples
This is a shorter chapter, and quite frankly we’re happy about that. There are few horrific stories out there about our fruits and vegetables. OK, formalin-sprayed mangoes, plastic rice and pesticide-laced aubergines aren’t great, but more than any other foodstuff we can control the fruits and vegetables we eat and reduce our vulnerability to food fraud. We repeat our mantra of ‘buy whole and buy from who you know and trust’.
More alarming in this chapter, however, is what we’re not allowed to see. How our basic fruits and vegetables are being processed, dipped in nanomaterials and other preservatives to fool us into thinking they are fresher than they are. As consumers we are not being given all the information about our food to enable us to make informed decisions. Is it assumed that we know there are processing methods out there that keep fresh food looking fresh well beyond what we know to be realistic? Or is it that they don’t want us to know? Surely it has to be one or the other. As consumers, if we had that information, wouldn’t we almost always choose the apple that rots?