36 MAY 2018
Sniffing that slightly shady mince
you’ve had in the fridge for one day
longer than safe may just be a thing
of the past if McMaster University
engineers and researchers have their
way. Academics from the Canadian
university have been working to develop
paper-based detection systems
to help consumers know immediately
if their dinner is still safe to eat. The
thin, transparent patches called Sentinel
Wrap are printed with harmless
DNA molecules or biosensors, and
affixed inside a package or container
of food. They remain stable for up to
14 days – long enough for perishable
foods to be packaged, purchased
and cooked. Lead study author Hanie
Yousefi says the biosensors change
colour when they detect harmful
pathogens, and handheld devices
such as smartphones can detect the
signals. “When the bacteria are present,
the DNA piece will start shining
and you can measure the light by a
smartphone or appropriate software,”
he says. Currently, the patches are
designed to detect two of the most
common and most harmful foodborne
pathogens, E. coli and Salmonella.
He hopes that food technologists and
manufacturers incorporate the biosensors
into the food they develop.
PAPER SNIFFS OUT BAD FOOD
THE SOURCE FOR FOODTECHNOLOGY INFORMATION
A large American egg producer
has recalled more than 200 million
shell eggs after at least 22 illnesses
linked to the eggs from its farm
in North Carolina. Rose Acre
Farms believes the eggs might
be contaminated by a dangerous
strain of Salmonella, which has
affected consumers in 10 states.
This represents the largest food
safety incident involving eggs since
2010, when more than 550 million
eggs were recalled after a nationwide
Salmonella outbreak sickened
thousands. “This recall is unsurprising,
even though eggs are frequently
tested for Salmonella,” Freedonia
analyst Cara Brosius says. “Farms
and processing plants use disinfectants
and sanitisers to prevent the
spread of dangerous pathogens,
but raw, whole shell eggs are not
commonly pasteurised in the US.
Pasteurisation of raw eggs in a
hot water bath can greatly reduce
the chance of Salmonella contamination,
but only processed egg
products such as liquid egg whites
must be pasteurised under current
USDA regulations.”
INDIAN MILK A WORRY
About a third of milk sold in India is
adulterated, and government testers
are worried that the situation will
cause widespread illness. Mixing
water into the milk, which increases
volume but decreases nutritional
value, is the most common adulteration
of the samples tested, but also
introduces bacteria or chemicals that
could have severe health consequences
for consumers. Other added
ingredients include detergent, foreign
fat, starch, sodium hydroxide, sugar,
colour and urea. India is one of the
world’s largest producers of milk, with
an estimated 165.4 million metric
tonnes produced in 2016-17. Demand
is expected to rise to about 220
million metric tonnes by 2022. Other
adulterated foods include tea powder
and spices. Last year, a feud broke
out between private dairy companies
in India and a government minister
who had publicly claimed the private
dairy companies were lacing their milk
with cancer-causing toxic substances
including caustic soda, bleaching
powder and formaldehyde.
EGGY
PROBLEM