featured in this issue - NZIFST - The New Zealand Institute of Food ...

after suffering a bout of foodborne disease compared to New
Zealanders – they accept their fate. This is important as it means
that reporting of foodborne disease in China will be different to
that in New Zealand where the sick may take a less philosophical
view of their plight. The style of cooking in China is also
different and may impact on the pattern of foodborne disease.
For example, Chinese people rarely eat uncooked vegetables
and generally eat food that has been recently cooked, i.e. with
no time for any surviving pathogens to grow. This contrasts
with New Zealand where many foods are eaten raw, and foods
which were cooked perhaps weeks ago, then packed, and cold
stored, are consumed regularly by many people. Published data
written in English on foodborne disease in China are scant, but
an analysis of outbreak data in one paper showed some stark
differences to New Zealand. For example, there are instances of
deaths attributed to intoxications by Pseudomonas cocovenenans
in China – an organism that is unheard of in New Zealand
as the food involved is not consumed here.
tube studies. The group has also looked at the ability of phages
to kill Shigella on foods and shown them to be effective against
three important species. Allied work on animal health has considered
the use of phages to control diarrhoeal disease caused
by Escherichia coli K88 and K99 in piglets and shown promising
results in a mouse model system. The group is also looking
at the potential to use phages to control various diseases caused
by Salmonella in chickens.
ESR has so far isolated a number of phages, including those that
infect L. monocytogenes, Salmonella, E. coli O157:H7, Campylobacter,
Staphylococcus aureus, Yersinia enterocoliticae and Y.
pseudotuberculosis, and Bacillis cereus. A broad view of potential
applications has been taken and work is underway, examining
the effects of viable phages, ultraviolet-inactivated phages
and phage-derived enzymes on foodborne pathogens. Some of
this work is summarised on the group’s site http://www.esr.cri.
nz/competencies/foodsafety/Pages/biocontrolfoodpath.aspx.
Scientific Paper
Mycotoxins
Workshop attendees learned about the situation with respect to
mycotoxins in China and New Zealand. Many kinds of mycotoxins
with different associated degrees of clinical significance
occur in a variety of foods. Mycotoxins form when fungi infect
growing or stored cereal (and other) crops and can produce
very serious clinical effects, for example, aflatoxins can cause
liver cancer.
Since aflatoxins may be present in peanuts, their presence is
significant for both countries as peanuts are a major trade commodity
for China, and New Zealand imports all the peanuts and
peanut products consumed here. It became apparent that quantitative
risk modelling is needed to allow the health importance
of the myriad foods and toxins to be clarified. ESR has capability
in risk modelling and this is seen to be of immediate use to
JAAS to help them assess the situation in their home province.
Researchers at JAAS have focused on controlling mycotoxins
produced by Fusarium spp. in wheat and have isolated a bacterium
which inhibits the growth of the fungus in laboratory
studies. Additionally, they have isolated a bacterium which produces
an enzyme that can degrade the mycotoxin produced
by Fusarium spp., deoxynivalenol. These findings present the
possibility of applying a biocontrol of the mycotoxigenic fungi
containing a component which retards the formation of the
toxin complemented by another which degrades it should it be
formed.
A quirk to the mycotoxins story is that if animals are fed contaminated
feed, some toxins can pass into the meat and milk.
It is therefore necessary to control the presence of these compounds
in animal feeds to ensure the safety of foods for human
consumption. Contaminated feed can be rendered harmless by
adding minerals which complex the toxins and allow them to
pass through the animal. In the future, it may be possible to
introduce a toxin-degrading enzyme to render feed safe or, perhaps,
to colonise animals with a stable population of bacteria
producing such enzymes.
Phage biocontrol of bacterial
pathogens
Scientists from JAAS and ESR described their biocontrol work
that uses phages to kill foodborne pathogens. JAAS has successfully
cloned an enzyme from a phage infecting Listeria monocytogenes
and demonstrated its ability to kill the pathogen in test
A food biocontrol web resource
The development of a website for both regulators and the food
industry is the other objective of the MFAT project. When biocontrols
become more widely used in the future this will represent
challenges in the assessment of their safety and efficacy.
The science and properties of biocontrols need to be de-mystified
in order for foods treated with them to be fully accepted.
While the website is still under development, the intention is
that it will be made publicly accessible as soon as possible, and
the link will be www.biocontrolfood.esr.cri.nz. Information on
the site includes that concerning the safety and regulatory position
of biocontrols in food. For example, descriptions and lists
are provided of those phage interventions which are Generally
Recognised as Safe (GRAS) in the US and conform to the Qualified
Presumption of Safety (QPS) in the EU. Some phage preparations
have been granted GRAS status, but phages in general
are not eligible for QPS status because of difficulties with determining
the identity of phage isolates. Discussion documents
and opinion pieces are provided which address the thorny
question of whether phages are additives or processing aids.
The site will eventually cover a comprehensive range of biocontrols
relevant to food safety applications, focusing primarily on
issues of relevance to trade between New Zealand and China.
We hope that other groups working in the same area may be
able to contribute towards the site, as well as forming a network
of FSB expertise within and between the two countries.
Dr Roland Poms, who is the co-ordinator of the EU project, MoniQA
(www.moniqa.org), attended part of the workshop. The
first contacts and cooperation activities between ESR and CCOA
were facilitated through the MoniQA Network of Excellence,
and the initial MoniQA-driven Memorandum of Understanding
between ESR and CCOA is being extended to JAAS, and refined
into concrete joint research activities.
Overall, the workshop was informative, productive and cemented
the relationships that had been previously established
between the partners. A tangible outcome of the meeting was
a written agreement charting the way forward with respect to
scientific collaboration. Areas of immediate common interest
were identified and strategies devised to continue the collaborations
between the organisations. The Powerpoint presentations
will be made available on the www.biocontrolfood.esr.
cri.nz website.
We would like to thank the MFAT for supporting this activity
and MoniQA for providing a travel bursary which helped Zhao
Yinli from CCOA to attend the meeting.
For further information contact stephen.on@esr.cri.nz
April/May 2011
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