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Acrylamide in food and drink

As the European regulatory framework on acrylamide in food and drink continues to evolve, Sterling Crew, Head of Technical at Kolak Snack Foods and Vice President of the IFST, reviews its origins, toxicology, management and control.

Acrylamide, acrylic amide, is an odourless white solid crystalline compound.with the chemical formula C3H5NO. Its IUPAC name is prop-2- enamide. It has widespread historical industrial use. Most acrylamide is used to synthesise polyacrylamides, which are used as water-soluble  thickeners in wastewater treatment, papermaking and ore processing. Some acrylamide is used in the manufacture of dyes and other monomers. The presence of acrylamide in food was first revealed when workers in Sweden, who were exposed to acrylamide in an industrial accident, were tested for acrylamide in their blood. Low levels were unexpectedly found in a non-smoking control group of unexposed workers. Researchers were intrigued by this anomaly and it led them to look for other possible sources. Acrylamide was surprisingly found in a number of commonly consumed foods, particularly those which were rich in carbohydrate and involved preparation by heating to a high temperature. The results were published in April 2002 and the occurrence of acrylamide in foods rapidly became an emerging potential global food safety issue. However it should be born in mind that this is not a new risk, acrylamide has been a ‘natural’ part of the human diet for thousands of years ever since foods were first prepared by cooking.

It became evident that the acrylamide was being formed in starchy food products during hightemperature cooking, including frying, baking and roasting. It forms at high temperature in the Maillard reaction between reducing sugars (fructose, glucose) and amino acids that are naturally present in plants and plant derived ingredients. Acrylamide is formed when free asparagine participates in the final stages of the reaction. The Maillard reaction is a form of non-enzymatic browning, which typically proceeds rapidly from about 140 to 165°C. The reaction is also enhanced by low moisture content. Free asparagine and reducing sugars are regarded as precursors of acrylamide but other amino acids can participate and sucrose can play a part if it is first hydrolysed. Acrylamide has been found in products, such as potato crisps, potato chips, bread, biscuits, cakes and coffee. Meat products are very low in acrylamide content as they lack the precursors required for its formation. It is interesting to note that cigarette smoking is a major source of acrylamide in humans and has been shown to cause an increase in blood acrylamide levels three times greater than that resulting from any dietary factor.

Due to its long term widespread industrial use, acrylamide’s toxicological profile has been extensively studied. Although it has not been established that acrylamide at the levels found in food is harmful to humans, there is a broad consensus based on animal studies that it potentially increases the risk of developing cancer. Acrylamide is readily absorbed and distributed to all tissues. It is metabolised to glycidamide, a clastogen epoxide, which can damage chromosomes. It can also combine with DNA and act as a potential mutagen. In 2010 the WHO/ FAO joint expert committee on food additives concluded acrylamide was ‘a human health concern’.

The Food Standards Agency’s (FSA) latest position is ‘Although acrylamide has caused nerve damage in people who have been exposed to very high levels as a result of occupational and accidental exposure through industrial use, it is less clear what the risks are from the acrylamide found in food. Acrylamide is considered to be a genotoxic carcinogen because it has the potential to cause cancer by interacting with the genetic material (DNA) in cells’. Based on independent expert scientific advice, the Agency believes that exposure to acrylamide in food should be as low as reasonably practicable. Given the uncertainties in exposure and the possible exposure to sources other than food, scientists have concluded that it is not possible to draw any definitive conclusions about the cancer risks presented by acrylamide in food. The European Food Safety Authority’s (EFSA) current position is ‘Studies on human subjects have provided limited and inconsistent evidence of increased risk of developing cancer. However, studies on laboratory animals have shown that exposure to acrylamide through the diet greatly increased the likelihood of developing gene mutations and tumours in various organs’.

Foods contributing the most to acrylamide exposure will vary around the world according to diet. The fact that a particular food product contains a high amount of acrylamide may not make it a major contributor to dietary intake if it is not eaten in large quantities. As Paracelsus’s classic toxicology maxim indicates ‘All things are poison and nothing is without poison; only the dose makes a thing not a poison’. Exposure data is normally calculated for gender, age and average and high consumers in each group. There are no statutory limits for acrylamide levels in food, however EFSA has introduced indicative values for those food groups considered to contribute the most to consumer dietary exposure. Indicative values are not maximum limits and are intended as a guide to initiate prompt investigation when higher levels occur.

EFSA’s Scientific Panel on Contaminants in the Food Chain (CONTAM Panel) is carrying out a full risk assessment of acrylamide in food. EFSA publicly consulted on their draft scientific opinion in mid-2014. It is expected that they will publish an updated opinion on acrylamide in food mid-2015. The opinion is expected to be similar in content to the draft, which was issued for widespread consultation. It is expected to confirm that, despite weak evidence for human epidemiology, acrylamide is a concern to public health based upon its carcinogenic effect on animals and the estimated levels of dietary exposure. It is likely that new legislation could be in place by 2016. The European Commission has recommended that Member States should continue to monitor acrylamide and as with previous surveys send the data to EFSA. EFSA has published an instructive infographic on acrylamide to help increase awareness about the issue. The infographic explains how acrylamide forms and in which foods, and includes basic tips provided by national authorities on reducing acrylamide exposure in the diet.

Management, control and ALARA
The European food and drink Industry has been cooperating on resolving the acrylamide challenge and has produced practical management solutions through the pan European tradebody FoodDrinkEurope. In 2005 it developed an Acrylamide Toolbox (latest version 2014) based on the use of the ALARA (As Low As Reasonably Achievable) concept, where food manufacturers use mitigation strategies to reduce acrylamide levels in their products. The four main categories for consideration are: raw material selection, recipe design, process design and finished product attributes. The toolbox is supported by other recognised sources, such as the CODEX Code of Practice for the reduction of acrylamide.

Clearly there can be no single solution to reducing acrylamide levels in the wide range of foods in which it is found. Looking at fried potato crisps as a case study, it is encouraging to see that there has been a significant reduction in acrylamide levels over the past 10 years. This has been achieved partially by using crisping potato varieties with consistently low concentrations of acrylamide precursors in the tubers. It is a major step forward in making it easier to ensure acrylamide levels that are towards the lower end of the range and below the 1000 μg/ kg indicative level set by EFSA. It is also clear from published literature that levels of reducing sugars in tubers are affected by storage, temperature, use of sprouting inhibitors, atmosphere and growing conditions. Manufacturers need to test the incoming potatoes and importantly apply the correct thermal input so that the fryer exit temperature is as low as reasonably practicable, without affecting the organoleptic nature of the crisp. The use of in-line colour sorting for finished product is also critical and a good investment as darker crisps are known to contain higher acrylamide levels.

European manufacturers cannot afford to rest on their laurels and still need to make greater efforts to drive further reduction in acrylamide levels in food and drink to keep up with the court of public opinion and an ever changing European regulatory environment.

For more information on acrylamide, read IFST's Information Statement.

Sterling Crew. FIFST. FCIEH. FRSPH is Head of Technical at Kolak Snack Foods Ltd and Vice President of the IFST.

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