Discussion on 3rd SUII workshop
Thursday 14th January 2016, University of Stirling.
Caveat: These were free ranging discussions and represent the
opinions of some, and not necessarily all, of the people in the
room. The discussions have not been fact checked!
The talks in this session were on:
Food safety in seafood:
Food safety fits across both terrestrial and aquatic systems. Impact of food borne pathogens on
human health is larger in different regions of the world. The opportunities for food safety issues are
equal globally but the impacts are not.
In terms of seafood food safety issues can arise due to contamination- this is the same for terrestrial
systems. However shellfish are a more unique system because they pick up environmental
pathogens through filter feeding. There is some similarity with roots in plants, but there are not the
same level of food safety issues in crops through this route- although lettuce and ecoli is an example.
Common questions about persistence of bacteria on food crops. How do bacteria interact with
plants/fish passengers or interactors?
Post harvest does not mean dead- live fish and live chicken markets are common
Geographical distribution of products in the supermarket for seafood is much wider than for
terrestrial animals. What are the food safety issues of this in terms of standardisation of testing
regimes etc. There are critical points at which testing takes place for all food species, (assuming
compliance takes place). Is testing done at a statistically significant level?
Supermarkets put down rules for how they should test and are very strict.
Heavy metals- more risk in wild fish- you cannot control where they eat and forage for their food.
Better in farmed salmon. However, depends on where they are and what species they are. We don’t
know what levels of dioxins are dangerous but we are very good at detecting them (good
instrumentation). Lots of studies in Vietnam of people becoming contaminated through eating wild
fatty fish and that pathway has been identified but that can be used politically. In farmed side you
get more consistent threshold but in wild fish more inconsistent.
Any food chain has got a risk of contamination. Provenance can help with that so routes can be
traced back.
Omega three in fish:
Fish feed- similar to fertiliser in concept –see SWOT discussion from first workshop- increasingly
difficult to source and important for healthy yield.
Nutritional value of fish in declining in some ways, is this happening in livestock and crops?
Any evidence- eg bananas some have higher nutritional values. Modern varieties of some crops eg
rasps and strawbs are larger and not as sweet.
Some plants eg potatoes have improved nutritional content- carbohydrate type and content because
of processing. Lots of characteristics are bred for. Pest and disease resistance etc
How is the health of soil – important for plant quality- equivalent to water quality for Aquaculture?
Aquaculture way behind in precision agriculture- you use what you have got. The more controlled
the food you give an animal (fish) the more you control you have over their quality.
Food security in the global south.
Many parallels between Dave’s talk in terrestrial and aquatic systems. Differences are: No physical
protection for aquaculture like wheat but unlike tomatoes and peppers ie no glasshouses.
What are most vulnerable parts of the life cycle for which it is important to invest in more
infrastructure, eg poly tunnels or fry in tanks
Pathogens risks to crop growth
We are going to need ag chemicals to grow the food we need.
Impact of pathogens on fish, there is a phasing out of fungicides for fish pathogens- equivalent to
what John has talked about.
There are similar organisms in both terrestrial and aquatic systems. Most plant pathogens are fungi,
fish- bacterial infections- vaccines, Sealice on salmon- chemicals – resistance. Sandy has new paper
out (put details here). Now focussing on biological control in fish- wrasse and lumpsuckers.
We are way behind terrestrial systems in our understanding of the host pathogen interactions in
Aquaculture-we try to control exposure of animals to pathogens during their production cycle. Treat
pond after the cycle to remove pathogens but you are also getting rid of good stuff, so you start
afresh every production cycle.
How do we look at ecosystems to understand interactions between hosts and pathogens and
emerging infections- are they caused by mutations or changes in our husbandry or are the animals
more resistant?
A lot of pathogens in fish are controlled through vaccination. You cannot vaccinate crops, but the
closest is GM resistance or normal breeding resistance. You can still do this in fish.
Similarities in behaviour between producers: to use, for example chemicals and then have to
respond to resistance rather than take an integrated approach. We have been round this cycle of
using the solution until it stops being a solution and then responding with a new solution.
IPM is being pushed at the moment as a good solution
How much transferable expertise do we have? Salmon disease (which one) is of great interest to flu
people? Map levels of expertise which cross over and in what way. One of the constraints is that in
Aquaculture is that growth, feeding rates etc are dependent on temperature. How do you approach
problems of disease identification and which disease is most prevalent now. Detection is difficult for
Aqua. Lots of work needs to be done to understand disease dynamics.
Densities are also important in crops- but optimal densities are well established.
Crop density is not about disease control, only about growth- this may also be the same in fish.
Mixed crops with different strains is a similar idea to herd immunity..
Intensive systems are perceived to have more disease problems and this is because they have more
to lose.
Other things we discussed:
Do the public ever get a balanced view of things? How do we communicate science in a balanced
way. Eg neonics
There has been a change in the way that risk is assessed in the EU- risk rather than danger- risk
threshold lower.
“We need to feed the world” but we need to distinguish the markets of the future. Science is
focussed on providing food for people who can afford to buy it. Some people will live on subsistence
farms.
Terrestrial animals have a very consolidated systems will this happen for aquaculture. This is already
in place for salmon. There are companies who close the system- eggs, feed, farms, processing plants
etc they have responsibility for everything, Pangasius gone from thousands of farms to two
companies doing most of the trade with EU.
In japan used to be more fish than meat has now changed from fish to meat (in 80s). Govt. took this
seriously because of health benefits- targeting schools . Campaign for beautiful young women going
round local villages to encourage eating local catch. Japan eat 60kg of fish per year. Strong cultural
affinity with fish consumption. But younger generation less able to prepare and cook and are put off
by preparation- fish traditionally sold Whole. One campaign is to teach how to cook fish in schools
since people no longer now how to do it. We do have seafood in schools initiative which may have
longer term impact. Birds eye and Youngs have done some with this- value added prodcuts (ie fish
fingers do well). Same in crop industry- potato waffles. Potato council does try hard to sell them
they are also available for value added products.
Difficult for fish to compete with chicken in terms of cheapness and flexibility of use. How do they
compete in the supermarket.
Animal welfare: 70% of Scotland farmed salmon is freedom food or RSPCA assured- more than the
proportion of terrestrial animals (approx 10% for pigs and poultry). Inconsistent between species
and places. How do welfare standards apply between food types. Don’t directly translate- for
example some species prefer high densities –they fight at low densities, and some prefer low
densities. We are only just starting to understand fish behaviour and how we assess it.
Different wrasse behave differently, some are better cleaner fish than others, but they need refuges
from salmon because they can be aggressive.
Postcode consumption of salmon is uneven. Is Scotland growing salmon in order to feed ourselves
or to export and make us money. Is the message about the enhanced omega 3 content in Scottish
salmon part of the advertising overseas?
Scottish dietary goals difficult to interpret in terms of what they mean in the real world.
More promotions of fish? Is healthy food really expensive? Good quality food is always more
expensive.
It would have been good to have more disciplines in the room to talk to us about this- food
technologists and psychologists etc.