The wide range of potentially harmful food process contaminants in modern diets is a growing problem for food producers and consumers alike. In this article, we explain what process contaminants are, and how they are formed during food preparation and manufacturing. We examine the leading process contaminants in food, with a particular focus on Advanced Glycation End Products (AGEs), and discuss how research and testing need to evolve in order to ensure the safety of the foods we eat.
What are food process contaminants?
Cooking and preparing food does not just allow us to enjoy one of the great pleasures of life, but is also essential to our well-being. As well as making food tastier, many ingredients must be cooked to be edible and digestible. On the other hand, in both home cooking and food manufacturing, processes such as baking, frying, grilling, smoking, or barbecuing can also transform what we eat in unhealthy and undesirable ways – generating “by-products that may cause mutations or various harmful diseases.” These by-products are known in food manufacturing as “process contaminants”, and are generated by a number of common chemical reactions, many of them involving heat – including the Maillard Reaction, lipid oxidation, and thermal degradation. As we shall demonstrate below, the increased uptake of food process contaminants is “emerging as a major problem in the modern lifestyle era” – by increasing the risks of carcinogenicity, genotoxicity, neurotoxicity, cardiovascular ill health and other adverse health effects in food consumers.
What are the main food process contaminants?
Here is our Top 10 of the food process contaminants that consumers, food businesses, researchers and regulators need to test for. For an in-depth look at Advanced Glycation End Products (AGEs), see the next section.
Our top 10 food process contaminants:
3-monochloropropanediols (3-MCPDs), 2-monochloropropanediols (2-MCPDs), their fatty acid esters, and glycidyl fatty acid esters (GEs), are processing contaminants found in refined edible fats and oils, particularly palm oil. In 2018, The European Food Safety Agency (EFSA) reassessed the possible effects of 3-MCPD on the kidneys and male fertility, finding that consumption levels in food were safe for most consumers. However, because of concerns about high consumption in younger age groups – in particular, infants only consuming formula – it increased its 3-MCPD Tolerable Daily Intake from 0.8 µg/kg body weight to 2.0. In 2017, EFSA also reaffirmed its position that GEs are genotoxic and carcinogenic.
4-methylimidazole (4-MEI) is formed during the caramelisation process in food production - for example, when coffee beans are roasted, meats are grilled, or certain types of caramel colouring are manufactured - and is considered a possible carcinogen.
5-hydroxymethylfurfural (5-HMF) forms in foods like baked goods, juices, coffee, and honey when carbohydrates are exposed to high temperatures, acidic conditions, or prolonged storage. 5-HMF can induce DNA damage, mutations, and cell death - raising concerns about its potential carcinogenic effects – and has been linked to diabetes, as well as neurodegenerative and cardiovascular diseases.
A highly reactive and toxic compound produced when fats and oils are overheated – particularly during deep frying, or when cooking with wood and charcoal – acrolein has been linked to respiratory irritation, lung inflammation, and neurotoxicity, as well as the development of asthma, chronic obstructive pulmonary disease (COPD), and cardiovascular disease.
Formed in starchy foods during high-temperature cooking, acrylamide is concerning because of its potential links to cancer, neurological issues and reproductive problems - prompting the consumer advocacy group SAFE to launch a campaign demanding stricter regulations. Despite the European Union (EU) accepting the need for legislation as long ago as 2017 – and reports last year that discussions were taking place on limits for acrylamide in foods like vegetable and cereal crisps – no action has yet been taken.
Found in fermented foods and beverages including breads, soy sauce, beer, and wine, ethyl carbamate/urethane is classed by the United States National Toxicology Program as “reasonably anticipated to be a human carcinogen”, based on data from animal studies. Consumers of alcoholic beverages are thought to be at higher risk of harm, although although the US Food and Drug Administration (FDA) says its evaluation of the compound’s health risks is continuing - given suggestions that ethyl carbamate levels in those products have decreased in recent decades.
Furans and alkyl furans are formed during when foods containing carbohydrates and lipids – such as coffee, canned juices or vegetables, processed meats and baby foods - are exposed to high temperatures. In 2017, EFSA carried out a new assessment of the health risks of furans in foods, confirming previous evaluations that they could lead to long-term liver damage.
Also known as HCAs, heterocyclic amines are formed when meat is cooked at high temperatures (i.e. above 150°C/300°F), and especially during barbecuing, frying and grilling. They have been linked to a higher risk of colorectal, prostate and breast cancer.
Nitrosamine – or n-nitroso - compounds can form during several stages of food processing, particularly in foods containing nitrites and amines that are exposed to high temperatures, acidic environments, or specific chemical reactions. They have been studied increasingly in recent years - with a focus on cured and processed meats including bacon, sausages, and ham, as well as smoked fish, cheeses and meats – because nitrosamine intake increases the risk of cancer, particularly in the gastrointestinal tract.
Created as both primary and secondary products during the incomplete combustion of organic material, polyaromatic hydrocarbons (PAHs) can contaminate grilled and smoked foods - and heighten the risks of lung, bladder, liver, and gastrointestinal cancers, respiratory problems, cardiovascular disease, and reproductive issues.
Contaminant Focus - Advanced Glycation End Products (AGEs)
As the nonprofit website NutritionFacts.org notes, it’s sadly appropriate that the acronym for Advanced Glycation End Products is spelt A-G-E.
That’s because AGEs are “gerontotoxins” – harmful food process contaminants that are thought to accelerate the ageing process by cross-linking proteins together in the body, thereby causing tissue stiffness, oxidative stress, and inflammation. In addition, AGEs have been implicated in the development of Alzheimer’s disease, as they appear to interfere with sirtuins – enzymes that promote healthy ageing and longevity – and aid the accumulation of plaques and tangles in the brain that are the hallmark of Alzheimer’s. “Older adults with high AGE levels appear to suffer an accelerated loss of cognitive function over time,” NutritionFacts says, adding that elevated levels of AGEs are also found in the brains of Alzheimer’s victims.
A Chinese study published last year agreed that “It is now well-recognized that excess accumulation of biological AGEs promotes oxidative stress and inflammation, and is closely involved in the pathogenesis of various chronic diseases.” It also argued that “ultra-processed foods which are replete with those ‘glycotoxins’ represent a link between diet and a series of pathological outcomes, (meaning that) the occurrence and metabolism of dietary AGEs are of high nutritional and clinical significance.”
Like many food process contaminants, AGEs form naturally via the Maillard reaction, but they can lead to harmful biological effects when produced in excessive amounts. Studies have shown that AGE formation is “closely associated with the presence of susceptible ingredients” – including simple sugars, fats, and high levels of proteins and carbohydrates – as well as “severer” manufacturing conditions like high temperatures and extended cooking times. Worryingly, the Chinese study found 10 major AGE compounds in 334 of the foods eaten most commonly in China and the West. It also reported that total amounts of AGEs in processed nuts, bakery products, and certain cereals and meats, were far higher (at > 150 mg/kg) than in dairy products, vegetables, fruits, and beverages (< 40 mg/kg).
The scientific response to the problem of AGEs has therefore become two-pronged. Some experts argue that, first of all, it is “essential to decrease the occurrence of AGEs in food products” - with spices, bioactive compounds, hydrocolloids, and even nanoparticles all suggested as promising ways of inhibiting or trapping AGEs. Other AGE mitigation strategies include marination and wet cooking, as well as switching to low-temperature cooking and natural sweeteners, or using antioxidant-rich additives like Vitamin C and polyphenols to neutralise AGEs.
A second way of limiting our exposure to AGEs and their harmful effects is – of course – a change of diet. NutritionFacts sees “avoiding high-AGE foods... as potentially offering a new strategy to combat the Alzheimer’s epidemic”, since even a modest reduction in meat consumption may be able to cut AGE intake by half. An Indian study published last year also noted that fruit extracts, vegetables and flowers may all inhibit the formation of AGEs – meaning that “it is suggestible (i.e., potentially beneficial) to incorporate vegetables, fruits, and edible flowers into the daily diet, especially for people consuming a meat-based diet.”
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The need for more food process contaminant testing and research
Process contaminants are an area where the need for additional research and laboratory testing is clear. As one study puts it, “The presence of hazardous chemicals in food poses a significant challenge to food safety and public health, underscoring the need for a deeper understanding of their formation mechanisms, potential health implications, and strategies for risk mitigation.” Moreover, as “(Processed) food preparation... is a long chain process, where each stage pos(es) a risk of accumulating hazardous contaminants”, it is essential that manufacturers, researchers and regulators all gain a better understanding of where, when and how process contaminants can occur in food products. When it comes to AGEs, for example, “Future research should prioritize refining AGE detection techniques”, and better characterising the complex process contaminants that form from different precursors. Meanwhile, “There is also a need to further elucidate the mechanisms that inhibit the formation of intermediate and end products of AGEs under food processing conditions”, as well as valuable work to be done on the clinical benefits of diets that are low in process contaminants.
Although regulation of many process contaminants is currently minimal or non-existent, food industry watchers believe that change may be coming - with organisations like the EU and the FDA actively studying the health effects of AGEs and other harmful compounds. Health-conscious consumers may also reward companies that invest in minimally processed foods which are low in contaminants, as well as “clean” labelling that gives customers the information they need to make healthier choices. As one future-facing article points out, “The global market for anti-inflammatory and anti-aging foods is projected to reach $300 billion by 2030. Consumers are willing to pay more for products with science-backed health claims.”
LGC Standards – supporting your process contaminant research and analysis
LGC Standards’ range of 200+ reference materials and analytical standards for food process contaminants features high-quality products from our trusted TRC, Dr Ehrenstorfer, and UK National Measurement Laboratory product lines. Our portfolio covers all of the main food processing contaminants, boasts more than 70 products accredited to either ISO 17034 or ISO/IEC 17025, and over 40 SILs – giving you confidence that your laboratory testing can help to keep food products safe for consumers.
Why not browse the table below for some highlights of our range?
| Process Contaminant Type | Product Link | Product Description |
|---|---|---|
| 3-MCPD | 3-Chloro-1,2-propanediol D5 | An ISO 17034-accredited, deuterium labelled neat from Dr Ehrenstorfer |
| 4-MEI | 4-Methylimidazole-d6 | A 98% purity SIL, with 90 Bioz Stars, from our CDN Isotopes range |
| 5-HMF | 5-Hydroxymethyl-2-furfural | An ISO 17034-accredited, neat reference material from Dr Ehrenstorfer |
| Acrolein | Acrolein 100 µg/mL in Acetone | A Dr Ehrenstorfer, single solution, ISO/IEC 17025-accredited reference material |
| Acrylamide | Acrylamide-2,3,3 D3 | A D3-labelled reference material from Dr Ehrenstorfer, accredited to ISO 17034 |
| AGEs | NEpsilon-(1-Carboxymethyl)-L-lysine | A neat TRC analytical standard with >95% purity, 90 Bioz Stars and 15 citations |
| Ethyl carbamate | Ethyl carbamate | A neat Dr Ehrenstorfer reference material with ISO 17034 accreditation |
| Furans and Alkyl furans | Furan-d4 | A deuterium-labelled, TRC analytical standard with >95% purity |
| HCAs | 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine | A >95% purity TRC analytical standard, with 92 Bioz Stars and 61 citations |
| Nitrosamines | N-Nitroso-dimethylamine D6 | LGC Standards | A D6 labelled, ISO 17034-accredited SIL from Dr Ehrenstorfer |
| PAHs | Chrysene-d12 | A D12 labelled, neat analytical standard from TRC - with >95% purity and 94 Bioz Stars |
