Writing in the journal Food Control, the authors said while different levels of aflatoxin contamination of almonds can be expected from year to year, their findings provide evidence of pre-harvest occurrence of aflatoxins in California almonds.
“This study confirms,” note the authors, “the importance of continued surveillance of AFs occurrence in almonds growing in California, particularly those growing in central and southern California.
The occurrence of AFs in tree nuts may be prevented or at least reduced with the use of Good Agricultural Practices (GAP) in the orchards, an approach encouraged by the Almond Board of California, added the US and Turkey based scientists.
Aflatoxins are extensively documented as a global contaminant of a wide variety of commodities including peanuts, maize, cottonseed, pistachios, spices, figs, almonds, pecans, walnuts and raisins.
Aflatoxins are known to be toxic to humans and are among the most carcinogenic substances known. High-level aflatoxin exposure produces an acute hepatic necrosis and can lead to liver cancer.
However, humans have a very high tolerance to aflatoxin exposure and rarely suffer acute aflatoxicosis.
Trigger for research
The study, remarked the authors, was prompted by the fact that there is little published data on the occurrence of these toxins in almonds collected directly from the orchards in that region.
They said that they analysed a total of 288 almond samples, collected from nine commercial orchards in California, for the presence of aflatoxins using high performance liquid chromatography with fluorescence detection (HPLC-FD).
The scientists report that they detected aflatoxins in 20 samples (6.9 per cent) from three of the nine orchards, both in 2008 and 2009 crops.
They added that the contaminated almond samples contained aflatoxin B1 (AFB1) at levels above the EU recommended level for safe consumption, while 16 out of 20 positive samples exceeded the maximum tolerable limit for total aflatoxins.
The team also compiled data on the exposure assessment of US population to aflatoxins from eating almonds, claiming their research to be pioneering in this regard.
But they concluded that the health risk from the estimated exposure levels was very low for US consumers.
“In the US, since the almond consumption is 616.89 g per year (1.69 g per day), and the average aflatoxins level is 3 ng g_1, the estimated daily intake of AFs through almonds by a 70 kg adult is 0.072 ng kg_1 body weight per day_1.”
California is the world’s major producer of almonds, representing 85 per cent of world’s production.
According to the 2009 Almond Board of California annual report, almond production in California exceeded 1.614 million pounds with about 86 per cent of the crop being exported.
And almonds are the number one horticultural export from the US, at close to $2bn in value in 2008, followed by wine and wine products, said the authors.
Western Europe countries are the main importers of US almonds, followed by Asia and Middle Eastern countries.
Source: Food Control
Published online ahead of print: doi:10.1016/j.foodcont.2011.04.012
Title: Occurrence of aflatoxins in California almonds
Authors: Kabak, B., et al.