‘An apple a day keeps the doctor away’ is a familiar adage to both children and adults, making apple and apple-derived products become popular foods among the crowd. Nevertheless, there are occasional news reports about patulin found in apple juice. As a symbol of healthy drink, why does it contain patulin?
What is patulin?
Patulin is a secondary metabolite produced by several species of mould mainly to the genera of Aspergillus and Penicillium. Experimental animals exposed to excessive patulin can cause visceral injuries and harmfully affect their immune and nervous systems. As for humans, ingesting large amounts of patulin from food may result in nausea, gastrointestinal discomfort and vomiting. The presence of patulin in food products poses a food safety concern owing to its adverse impacts on human health.
When fruits (e.g. peaches, pears, grapes and especially apples) are damaged or rotten due to improper storage and transport conditions, they may be contaminated with patulin. In recent years, there have been food safety incidents in Australia, New Zealand and Hong Kong, where apple juice products were found to be contaminated with patulin. Although the apple juice is filtered and heated for pasteurization before packaging, the patulin which is already present in the raw material cannot be removed or destroyed. If apples contaminated with patulin are made into juice, the patulin is likely to exist in the final products.
Regulation of patulin
In 1995, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) established the provisional maximum tolerable daily intake (PMTDI) for patulin to be 0.4 µg per kilogram of body weight. In this respect, the Macao SAR Government enacted Administrative Regulation No. 13/2016 “Maximum Limits of Mycotoxins in Food”, based on comprehensive analysis on those findings of scientific studies, researches and food consumption surveys across the world. According to this Administrative Regulation, the permissible maximum limit of patulin in products derived from apple and hawthorn (Crataegus pinnatifida), as well as in juice or juice beverages made from apple or hawthorn (Crataegus pinnatifida), is 50 µg/kg.
Preventing the growth of mould in fruits is an effective way to reduce the likelihood of patulin contamination in juice and its derivative products. So, it is necessary to store harvested fruits at the appropriate temperatures and conditions, as well as avoid bruise damage caused by excessive compression. If mould is found on the surface or inside of fruits, do not consume or use them for food processing. Always discard mouldy fruits, regardless of the amount of mould present. Buy fruit products, such as fruit juice and jams, from reputable brands. Consume them as soon as possible after purchase, and store in a suitable environment.