Study pinpoints cashew allergens which survive processing

By Caroline Scott-Thomas


Source of Article:


10-Oct-2008 -

Researchers at Florida State University have found that key proteins in cashew nuts survive even after processing, which may lead to more accurate detection of allergens in mixed ingredient food processing environments.

The study, which was led by Dr Shridhar Sathe, pinpointed the three major allergens in cashew nuts and established that they are still present following common processing methods, such as blanching, pressure cooking and dry roasting, meaning that they could be used as markers to detect cross-contamination even in small quantities in processed foods.

Referring to those in the food manufacturing industry in particular, Dr Sathe told “One particular point the manufacturers need to be aware of is the possibility of ‘hidden allergens’ in the ingredients they use in their manufacturing. Inadvertent and undeclared presence of an offending agent is a concern in all food manufacturing operations.”

The findings appear in the latest Journal of Agricultural and Food Chemistry.

Severe reaction

Allergic reactions to cashew nuts are generally more severe than those caused by more common peanut allergies, with 74.1 per cent of cashew-allergy sufferers experiencing anaphylaxis compared to 30.5 per cent of peanut-allergy sufferers, according to a study released last year. There is currently no cure for nut allergy, so the only way for allergy sufferers to eliminate risk of reaction is to entirely avoid contact.

Dr Sathe’s research notes that: “With their global popularity and increased use, risk of inadvertent exposure to cashew nut seeds is likely to increase…Developing simple, specific, robust, accurate, and reproducible detection methods is therefore essential to safeguard sensitive individuals from unintended exposure.”

The fact that allergy sufferers are extremely sensitive to even minute quantities of cashews in foods, means that food processors need to apply the “may contain nuts” warning label to all products handled in an environment where cashews are present, even where the risk of cross-contamination is slim.

‘Hidden allergens’

This latest study builds on Dr Sathe’s previous work in developing a bank of marker proteins for a variety of nuts, although that research did not allow for investigation of specific nut allergens.

The new research has the potential to be used by the bakery sector to allow for more accurate testing for the presence of these marker proteins, thereby identifying so-called ‘hidden allergens’.

Dr Sathe added: “Detection methodology needed to determine presence of trace constituents…is a major challenge for all.”

The study involved developing mouse monoclonal antibodies specific for the three cashew nut allergens, Ana o 1, Ana o 2 and Ana o 3. After processing, the researchers discovered Ana o 2 to be the most stable. Due to this stability, as well as it being a major allergen in cashews, they found it to be the best marker protein for cashew detection.

Cashews are not only increasingly popular as a snack but also as an ingredient in many bakery products and processed foods throughout Europe, including cereal bars, desserts and commercially produced pesto sauces. Current EU cashew consumption is now over 2m tonnes per year, according to FAOSTAT figures, an increase of almost 30 per cent from a decade ago.


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