Hello, I'm Michelle Tapper with the Latest from Science. Food waste is a major global
problem with about one third of all food that's produced ending up as waste. In Australia,
it costs the economy about $20 billion a year, and it also has serious environmental consequences.
Joining us today to discuss these issues is Dr Polly Burey, a food scientist from the
University of Southern Queensland. Hi, Polly. Thanks for joining us.
Hi Michelle. Thank you for having me along to talk about a topic that's quite near and
dear to me, and probably affects quite a few people out there as well.
Now, a lot of people are probably unaware, just how much impact food waste has on greenhouse
gas emissions. How bad is it here in Australia?
So in Australia with all our activity, we produce about 500 million tonnes of CO2 equivalent
per year. In Australia, in terms of food waste, we produce about 8 million tonnes of food
that might be wasted. And off that 8 million tonnes, we're generating 15 million tonnes
of that CO2 equivalent, contributing to that 500 million. So it's only like a few percent,
but putting it in perspective, it's actually more than what our steel and iron ore industries
produce, which is really quite significant when you think about it. And when you think
of how much energy and effort goes into producing those things, our food waste actually produces
more greenhouse gas emissions than that does.
What can people do at home to reduce their own food waste?
Okay, well, there's a few strategies you can use at home. And I guess the first one is
prevention is better than cure. So one of the first things you can actually do is try
and prevent food waste being generated. So you can do a lot of planning for your shopping
for the week or the fortnight for your food usage and only buy or source o what you need
and use it up while it's fresh or while it's within the date of usage. One of the issues
typically is that things like fresh produce tend to spoil quite quickly. So your berries,
they really only last a couple of days or so in terms of quality, some veggies can last
about a week or so and some a little bit longer. So first of all, try and use everything that
you buy. Second of all, if you still have stuff left over, there's a few things you
can do.
And you can borrow some processes from the past, and from the food industry. So there's
a few things you can do. You can cook and chill your food, and then eat that over the
week. And it's lasting a little bit longer than just your fresh produce. You can cook
and freeze and that lasts a couple of months or so, depending on what it is that you're
actually cooking. Now freezing can work for quite a few foods, but for some things like
tomatoes, it's not ideal because they turn out pretty mushy and horrible. Some of the
things you can do, if you're into that kind of thing, you can do some canning or preserving,
and that can work for both fruit and vegetables as well. With your meats, you can make things
like beef jerky and so on, and they last a lot longer than just fresh meat.
You can do things like fermentation and pickling, and the good thing about fermented foods as
well. There's a lot of healthy compounds in there as well. Not just that your food's shelf,
life is lasting for quite a while. And then another thing that you can actually do is
dry your food. And that way you're reducing the level of water in there. So your nasty
bacteria and all sorts of things that would spoil the food otherwise can't do their job.
And so that means your food quality and your food safety is prolonged. However, you might
still have some stuff that actually did spoil and get a little bit horrible, and that's
when you can start getting into things like producing compost. But typical backyard compost,
you've got to do it properly. If you just dump it on there and just leave it, that's
actually not going to do much good, it's just as bad as a landfill. Because you're going
to be producing some methane and all those other little greenhouse gases and things.
So if you're going to do compost, make sure you learn how to do it properly. It does need
to be turned and aerated. Sometimes you see those barrel-type compost bins that tumble,
and that's the reason for it to keep it aerated and to keep it healthy.
Well, that's all really helpful advice, but what about supply chains and grocery stores?
What issues do they have and how can they help produce food waste?
So supply chains in Australia can be quite tricky sometimes. It can be quite a bit of
distance from where the food is produced to where it ends up being sold. And so during
that journey along the supply chain there's actually quite a lot of points where there
could be waste generated. So it might be generated on farm, which I'll talk about in a moment,
it might be generated while it's travelling on the truck and stuff got thrown around a
bit and maybe bruised that can affect quality and it might not be saleable. Then, you know,
they're obviously packed a certain way to try and prevent that, but there's always a
little bit of damage. Once it hits the shops, there's a little bit more handling to get
your food out on the shelves and so on. Sometimes things get dropped, sometimes things are left
too long.
People in the supermarket tend to, and they say they don't, but they tend to pick over
to get the nice looking apple or the nice looking tomato and so on. So if you saw for
example, a cut on something, and you're worried about what that might mean for safety or how
it looks or how it will taste, people do tend to avoid that, for the most part, so that's
one of the issues. Probably the major issue with a large sort of grocery store chains
is that they've got a lot of food there, potentially it could be waste. Some of the worst categories
are actually a fresh produce, which I mentioned earlier, because it can go off quite quickly.
And bread is one of the other big categories as well. That can be wasted too. So I think
with grocery stores, it's the collation or the collection of a heap of food, all in the
one place trying to be distributed quite quickly sometimes. And if it isn't in time or then
yeah, it just ends up being wasted.
There'll be going back to the beginning of the supply chain from a farming perspective,
how can food waste be improved upon there?
Okay, now farming can be really tough. And sometimes the issues that cause food waste
on farm are actually outside of the farmer's control. So one thing a farmer can't control,
they can't control the weather. So if it gets hot too soon, that means their produce may
ripen or mature sooner than planned, which means that their scheduled pickers can't arrive
in time, which means the produce is ripening and it's extending into getting towards spoilage,
and that's something they can't control. What we need to do to maybe tackle that is to in
a way, and this is where my research starts getting into it, bring a processing or preservation
capability to the farm, where there is the tonnes of food being produced that may become
waste. So one of the issues, and this is when I first started working on this problem, with
the pineapple industry every few years, the weather patterns caused them to ripen quite
quickly and quite early.
And that means that they end up with a glut at which might not be usable in time. And
one of the criticisms sometimes is that our factories won't take these. They just won't
take them. But the reason being is that they're scheduling in these factories and there's
limited factories as well. So at the moment in our, I guess, processing side of our food's
supply chain, there, isn't the flexibility to deal with something like this. So one way
to get around this is you can have, I guess, mobile processing in a way to deal with an
unexpected glut for that period of time. And then it goes away and can be used to deal
with another problem. That's one strategy. Another is the farmer themselves can start
moving towards value-added products. So not necessarily just fresh produce, but they could
have some of those things we talked about.
Like they could be making pickles, they could be making preserves they could be drying,
et cetera. And some farmers are actually already doing these kinds of things and solving some
of their waste problems themselves. So those are some ways that could be used to use up
the waste. As to how to reduce it. Well, there are some sad stories out there. So a couple
of years ago there was a study done on Sunshine Coast, where some of the tomato growers had
more than 80% of the produce didn't meet spec. So that meant 80% of it didn't get sold, didn't
get eaten. Now, as you can imagine, that's quite significant. And as a result, some of
them actually stopped growing tomatoes, not an ideal strategy for reducing waste. But
it is one that has been used in the past to say, we don't want this to happen again, the
way to stop it might actually be to stop growing up. And then there's a couple of other reasons
that can cause waste. So a couple of years ago we had the strawberry issue in Queensland
with the needles found in strawberries. That was not the farmer's fault. And that was something
that was not foreseen. Problem was not only the farms that had the issue were affected,
but all strawberry growers were affected. So again, something outside of their control,
what can they do? So the only thing they can do is check all their produce, potentially
send it to you know, a second tier product, like a powder or a jam or something like that,
and try and recover something, in terms of value and in terms of the food being eaten
as well,
You do a lot of research and creating value from food waste. Can you tell me about some
of the innovations that you've come up with?
Okay. So my research team focuses on ending value to food to the point that there's no
waste at all. So just thinking, you know, for example, for your potatoes, a lot of people
tend to peel the potatoes. So there's what we call a byproduct where, you know, you don't
typically tend to eat peel even though you can. And so we focus on not only the, the
edible part, but the part that people sometimes don't consider edible and what can be done
with that. So the areas that my team tend to focus on—we have our first stage, which
is normally the capturing of the food to prevent it being wasted and preserving it. And there's
a few technologies we work on without industry collaborators. So some involve special drying
technologies, which don't affect the nutritional content of the food. So typically if you dry
a piece of fruit in an oven, you've lost pretty much all the, a lot, of the useful vitamins
that would eat otherwise get from a fresh piece of fruit, but there's ways to do that
and still preserve that.
So that's the first stage of our research. We have a second stage, which actually focuses
on extracting compounds that are useful for nutritional and pharmaceutical uses in some
cases. So there's some compounds and things like apples and bananas and strawberries,
which in some research studies, admittedly lab bench studies, that have some activity
on conditions like diabetes, like cancer, like heart disease, et cetera. And so on and
so forth. Some of these compounds are actually well-established as having medicinal properties
and are out there in the market and synthetic forms, but our foods that doesn't don't get
eaten, can actually be a source of these and how to extract these, I guess, in an economically
viable way, it's one of the challenges, where us engineers and scientists deal with. So
that's the second tier. One arm of it also is fermentations.
So, I did some calculations a while ago and said, if we took all our potatoes and we turned
them all into gin, we would have several million litres and we'd be literally drowning in gin.
That's wonderful, but it's not ideal. So one thing we can actually do with fermenting,
something like potatoes or another starchy or sugary type produce, is actually produce
ethanol. Now ethanol has a few uses. You can use it as a biofuel. You can use it for a
clean product. You can use it in hand sanitiser as we've found most recently. But one thing
with the ethanol is we can actually feed it back into our second stage process to do the
extraction. So one thing we do in our modelling, as we can say, okay, we have a waste stream,
we can dry part of it. And that's one of our products and it's worth X amount. We can take
that dry product and we can extract something else out of it and that's worth Y dollars.
And then we can take another part of it, produce that ethanol to extract that compound, and
that produces a certain amount of value as well.
Those are some amazing products. Now you also make bio-plastics from food waste. How does
that help the environment?
So your food wastes have a few substances in there called biopolymers and your traditional
plastics are just normal polymers from petroleum. Now one of the things we can do is we can
extract some of these biopolymers from our food waste and turn them into films. So a
couple of years ago I had a student working with some orange peel, and she extracted some
pectons and some cellulose, which has some of those biopolymer molecules in them. And
she made some bioplastics. Now I've got some right here. So this one here was made from
orange peel. Now, when she was doing that project, she said, "Oh, I think I've failed
a bit as a plastic. It's not very dry". Some of the samples she created were actually like
a hydrogel, and hydrogels have really good applications in wound healing and medicine
as well. So not only can we use it for a packaging-type application, but we can also go so far as
using it for a medical application as well.
Now, obviously these are great and creative uses of food waste, but are they a sustainable
solution to the problem? Or do we just need to go back to the very beginning and reduce
our food waste in general?
So some of these solutions, if we overcome the cost of producing some of these materials
and substances, then they would be a sustainable solution. And that's part of the, I guess,
technology and research development to get to that point where it's competitive with
alternatives, which are a lot cheaper. So thinking about your bioplastics, your bog
standard, just plastic bag is really quite cheap compared to how to produce a bioplastic.
So that's one of the challenges to overcome. And once that is, then yes, it would be a
sustainable solution. But your point about reducing food waste in general, that's definitely
a very wise one. So if we stop creating the problem in the first place, that means we
don't have to deal with amount of stuff down the line there. And in fact, in the hierarchy
of dealing with waste, reduce is probably at the top. And then we start getting down
into some of the strategies that I talked about today.
Thanks so much for all of that really important information and for stressing the importance
of reducing, reusing recycling and repurposing. Dr Polly Burey thank you for your time.
Okay. Thank you for having me, Michelle.
And don't forget for regular video updates from the Australian Academy of Science, make
sure to follow us on social media. I'm Michelle Tapper, see you soon.