Preserving food when plentiful, to prepare for leaner times, is an ancient practice. There’s evidence cultures in the Middle East and China were using the sun and wind to preserve food such as fish, meat, fruit and vegetables, as far back as 12,000 years ago.
Widely use by combat troops during World War II, dehydrated food, unsurprisingly, fell out of favor with the public after the war. It wasn’t until the cultural revolution of the 1960’s, with a renewed focus on all things natural, that dehydrating foods experienced a renaissance of sorts.
As with all food preservation methods, there are certain steps along the way that present safety issues. Sourcing, producing and storing dehydrated fruits, vegetables and other produce correctly is important. It keeps the food, and the humans who consume it, safe.
Dehydrated food is cool again. You only need to check the fruit, veggie and health food aisles. People are living busy lives and want portable, tasty and healthy snacks. And not just snacks. Meals resembling grazing tables are almost the norm in some homes and offices around the world.
With the seemingly endless array of food and diet fads, if people can’t make their own food, they want to know what goes into the foods they do buy.
So, it goes without saying, that means sourcing quality produce.
There’s never been a better time to support local business and buy locally grown, seasonal produce as often as possible. Farmer’s Markets are a great place to start. You can find local markets here.1
Buying in season means you’re:
Not sure what’s in season? Check out this seasonal food guide2 to see what’s best at different times of the year throughout Canada.
The Canadian Food Inspection Agency3 is responsible for regulating fresh fruit and vegetables imported into Canada. All products must meet Canadian requirements, with some products from specific geographies with elevated safety risks having specific requirements including leafy greens, raspberries, cantaloupe and coriander.
Before engaging with an importer who brings in fruits and vegetables from outside of Canada, it’s a good idea to ensure they have the appropriate permits, including membership with the Fruit and Vegetable Dispute Resolution Corporation. This gives you the best chance of protection.
The Canadian Food Inspection Agency4 links to recommended codes of practice for the packaging and transport of fresh fruits and vegetables. It’s a good idea for producers of dried fruit and vegetable products to be familiar with these guidelines to maximise safety throughout the chain from sourcing through to processing. The code covers factors like:
It’s worth noting that specific recommendations are in place for ready-to-eat fresh pre-cut fruits and vegetables, as well as sprouts, fresh leafy vegetables, melons and berries. Please review the code if you will be sourcing these products.
It’s worth familiarizing yourself with cold chain principles for the storage of fruits and vegetables throughout the process. As The Global Cold Chain Alliance5 says:
‘The cold chain refers to the management of the temperature of perishable products in order to maintain quality and safety from the point of slaughter or harvest through the distribution chain to the final consumer.
The cold chain ensures that perishable products are safe and of a high quality at the point of consumption. Failing to keep product at the correct temperatures can result in a variety of negative attributes including, among others, textural degradation, discoloring, bruising and microbial growth.
Each sector of the chain, from the point at which product is harvested to the point at which it is sold, shares responsibility.’
The Canadian Food Inspection Agency6 recommends refrigerated food be maintained between 0°C and 4°C and frozen food at -18°C or less.
Those in the cold chain should also regularly review policies and operating procedures as part of Hazard Analysis Critical Control Points (HACCP) and internal Food Safety Programs.
Originally developed by NASA and a group of food safety specialists in the ‘60s, Hazard Analysis Critical Control Point (HACCP) is an internationally recognized food safety and risk assessment plan. The plan outlines seven key principles in food safety:
Following HACCP plans isn’t mandatory. However, with many farms shifting towards production, more kinds of food businesses may need to adopt HACCP plans.
Some fruits, such as apples, bananas, nectarines, pears, peaches and apricots will benefit from some pre-treatment before drying. Pre-treating with an acidic solution like citric acid or ascorbic acid will:
Other methods of pre-treating are:
The drying process removes moisture from the food. This also hinders the growth of mold, bacteria and yeast and ensures the dehydrated fruit and vegetables don’t easily spoil.
A major contributor to drying food is humidity. As drying involves removing the moisture from the food and releasing it into the surrounding air, low humidity helps the drying process. This is why the drying of foods originated in the warmer and drier countries around the planet. Higher humidity will slow down the drying process as the air would also be heavy with moisture. Increasing air flow can speed up the drying process.
Water activity (aw) is a measure of available water in food. That’s not as simple as how much water is in the food though, as some water is bound to other ingredients – like sugar or salt – and isn’t available. In the context of dehydration, this is important as it is the available water7 that microorganisms will use to facilitate growth.
When too much water is available, microorganisms can grow. Pure water has aw = 1.00 and fresh fruits and vegetables have aw = 0.98. The FDA8 recommends drying fruits to aw = <0.85 to 0.60 and drying vegetables to aw = <0.60.
The safest and most accurate way to monitor water activity is by using a water activity meter. It is also possible to measure weight loss to determine moisture loss, but this is not recommended for commercial applications.
The Canadian Food Inspection Agency provides a food labelling tool9 to help producers navigate specific requirements. This includes:
There are also specific requirements for processed fruit and vegetable products.
Correctly prepared, dehydrated and stored dried fruits and vegetables typically last a year or even longer. Vegetables tend to have a longer shelf life than fruit. Stored at stable temperatures in a cool, dark spot will increase their shelf life. Those foods with the least moisture content will last the longest and vegetables that are cooked prior to dehydration tend to last longer as well.
Should a package show condensation or other signs of moisture, if it looks unusual or smells funny, it’s likely to have spoiled. And if it’s moldy, throw it away immediately.
There’s a few basic principles to adhere to in any environment where meat and food products are being prepared. These include:
The highest hygiene standards should be maintained every step of the way.
Best practice is to clean it between every batch. The trays in our dehydrators are dishwasher safe and the insides of the dehydrator should be cleaned using a cloth and warm soapy water (being careful not to splash water onto the electrical parts). We recommend using a food-safe sanitizer spray to eliminate microbial growth.
Any cleaning chemicals should be appropriately stored. Staff should be trained how to use cleaning chemicals safely, so as not to cause accidents or contaminate foods.
It’s also important to ensure equipment is thoroughly dried after cleaning to prevent Listeria contamination.
As well as daily cleaning, including throughout the day, regular cleaning and sanitizing should be scheduled for things like cool rooms and drains. It’s also a good idea to regularly clean shelving in chillers, door handles, door seals, switches.
All equipment used for monitoring should be regularly checked and calibrated to ensure accuracy. This includes:
If you’ve any questions about cleaning your commercial dehydrator, recommended settings, or other aspects to ensure a safe final product, let us know. We’re here to help guide you to producing dehydrated foods that are delicious and healthy.
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