Nuts

How fresh?

Most nuts sold here are imported. That means it may be a long time and distance from farm to table.

Nuts past their best have an unpleasant taste. If you’ve ever bitten into an old walnut you’ll know what we’re talking about!

Of 30 products we sent to the lab, all passed our freshness test.

But finding out where nuts you buy are from, and how long it’s taken them to get here, is harder than it should be. Few products list a country of origin and none give a “packed on” date.

Ceres Organics Raw Whole Cashews was the only packaged cashew in our test to give a country of origin.

Pak’nSave and New World displayed this information at point-of-sale for bulk bin cashews. But other brands had vague statements, such as the cashews were packed in New Zealand from imported ingredients. It was a similar story with walnuts.

When we asked for the information, most companies provided us with the country of origin. Vietnam was the most common source of cashews. Most walnuts came from the United States.

Several companies said the country could change due to fluctuating prices, crop failure and availability, which they claimed made it difficult to have one source on the packaging. But the clock’s ticking on that argument. If legislation before parliament is passed, origin labelling on all single ingredient foods will be made mandatory.

The aflatoxin issue

Freshness isn’t the only issue when it comes to nuts. Nuts can be affected by aflatoxins, naturally occurring toxins produced by a mould that can grow on nuts, seeds and grains. Aflatoxins are a concern because they are carcinogens.

In a 2010 survey, the Ministry for Primary Industries (MPI) detected aflatoxins in 41% of peanut butter samples and 20% of peanuts, 27% of mixed nut products and one sample of brazil nuts and pistachios. None were detected in almonds and cashews. Two samples of raw peanuts and two peanut products had aflatoxin levels that exceeded the maximum permitted limit of 15mcg/kg.

MPI monitors and tests imported shipments of peanuts and pistachios, and products made from them, such as peanut butter, as well as mixed nuts containing peanuts.

“Shipments are stopped at the border and inspected for visible signs of mould or insect infestation, and then sampled and tested at the importer’s expense. If aflatoxins are detected, they must be less than a certain level or the shipment is rejected. Out of 873 consignments of peanut and pistachio nut products imported in 2016, 32 were rejected,” an MPI spokesperson said.

MPI toxicology and environmental chemistry specialist adviser Dr Andrew Pearson said aflatoxins appear as green mould but lab testing is required to confirm their presence.

As a general food safety rule to prevent fungi or mould, nuts should be stored in a sealed container in a cool, dry environment, he said.

In 2011, MPI published an assessment of New Zealanders exposure to aflatoxins. It concluded we’re exposed to levels at the low end of the international range. Risks of liver cancer (the main concern with aflatoxins) were very low – about one-in-a-million chance over a 78-year lifetime.

Chemical residues

Imported nuts may also contain residues of propylene oxide (PPO). The US requires raw almonds and some pistachios to be pasteurised with PPO. The chemical, used to kill salmonella bacteria, may also be used by other countries exporting nuts to New Zealand.

MPI testing in 2011 and 2012 of 261 raw whole nuts found 18 samples had PPO residues. Levels were below limits approved by US regulators.

Dr Pearson said the PPO residues found by MPI’s test were not considered a health risk when assessed against the 2011 acceptable daily intake set by the Joint Food and Agricultural Organisation of the United Nations and World Health Organisation.

Bulk bin vs pre-packed

When it comes to price, buying from supermarket bulk bins isn’t always cheaper. On average, the cashews in our test were $3.53 per 100g. But bulk bin cashews from New World and Pak’nSave were slightly more expensive. For walnuts, the average cost was $3.71 per 100g. Bulk bin prices at Countdown stores we visited were about $4. Check the unit price before you buy to see which option could save you the most money.

Nut nutrition

Nuts are nutritional powerhouses. As well as being a good source of protein, they also have fibre so keep you feeling fuller for longer.

All nuts are healthy, but the different kinds have different nutritional bonuses. Walnuts are rich in omega-3 fats; cashews are highest in zinc; and brazil nuts packed with selenium.

For good health, it’s recommended you eat one serving (about a small handful or 30g) every day. According to the Heart Foundation, regularly eating nuts may play a protective role in improving risk factors for heart disease and lower cholesterol in people with raised levels.

Raw nuts are the healthiest choice – not nuts roasted in oil or covered in salt. Nuts are a high-kilojoule snack, so limit yourself to a small handful.