Day 10
You should spend about 20 minutes on
Questions 1-13,
which are based on Reading
Passage 1 below.
A brief history of canned food
In 1795, the French government had a problem: they faced the fact that it is not easy
to win battles abroad when your soldiers are hungry and malnourished.
That year they
established a 12,000-franc prize for whoever could find a way to preserve food - from milk
and meat to fruits and vegetables. French chef Nicolas Appert took more than a decade
to develop a process that involved cooking food in glass jars and then using seals made
of cork to make them airtight. In 1810, he published a book whose title translates as “The
art of preserving all animal and vegetable substances for several years”, and collected
his prize money. Appert’s achievement didn’t escape the notice of British merchant and
inventor Peter Durand, who applied for a British patent later that year.
Durand used
techniques similar to Appert’s, although he adapted the model to include the use of tin
vessels as well as glass jars.
Following these discoveries, canned food was initially produced for soldiers and explorers.
But even after people became aware of the existence of bacteria in the late 19th century,
canning companies couldn’t work out exactly why some of their turned bad. And even into
the 20th century, newspapers were full of accounts not only of food poisoning but also
of cases of the fatal disease botulism resulting from people eating canned food. For that
reason, many continued to look upon canned food with suspicion and fear.
The US food manufacturer, The Heinz Company, realized bad cans were bad for business.
From the 1890s to 1920s, the company insisted on weekly manicures for its canning-
factory workers to ensure that any bacteria beneath employees’
fingernails stayed out of
the food. Heinz employees were required to shower and change their clothing regularly.
In an era when food-factory hygiene was not universally adopted, what might have been
considered a nuisance by workers was at least good for consumers.
Some canning companies killed bacteria with chemical additives such as sodium
benzoate, which is still used today in canned food, and formaldehydes, which are now
known to cause cancer. Some of the
larger canning companies, such as Heinz, Libby, and
Campbell’s, installed expensive steam-retort technology developed in the 1870s. Steam
retorts worked like steam engines, using pressure to raise canning temperatures high
enough to make food safe. Yet some batches of cans, even when made with this advanced
technique, would explode after months on the shelf, while the contents of other cans might
mysteriously sour. Smaller canning manufacturers relied on the open kettle method* and
they had even less consistent results.
*open kettle method: food is cooked in a covered container and then poured
while hot into sterile jars
Reading Passage 1
US canning companies eventually banded together to discover the scientific principles
affecting the canning process. In 1913, they launched the Research Laboratory of the
National Canners Association in order to look into the elusive bacteriology responsible
for all manner of spoiled canned food. The research done by the laboratory in the decades
that followed helped resolve the problem of spoiled food and led to improved flavor, color,
nutritional value, and texture.
Before this time, canning companies had discovered through trial and error that the
best way to avoid bad cans was to cook food at high temperatures for long periods, an
approach that sacrificed flavor. ‘Food safety and palatability were
often at cross-purposes,’
remarks food historian Gabriella Petrick. For string beans, for instance, long cooking
times in hot water leach out the green color, creating an unattractive grayish- toned bean.
The addition of salt was one technique employed in the early 20th century to prevent this
happening, thereby maintaining the visual appeal of the product and restoring a certain
amount of taste.
One of the major canning innovations of the 20th century was the
development of aseptic
processing. This technique, which involves sterilizing the container separately from the
food, was invented in Switzerland in the 1960s for processing milk, but is now used widely
for canned tomatoes and many juices. Small volumes of food are heated to a precise
temperature and for a precise time in order to avoid overcooking and preserve color and
nutrients, explains food scientist Philip Nelson, who won the 2007 World Food Prize in
recognition of his research on making aseptic processing workable
on a large industrial
scale.
Today, despite all the modern alternatives, Appert’s technology still reigns supreme for
long-term storage. More than two centuries on, the simple can is still the best solution for
the safe and effective preservation of a wide range of foodstuffs worldwide.
Choose ONE WORD ONLY from the passage for each answer.
Write your answers in boxes 1-8 on your answer sheet.
S o lv in g p ro b le m s in th e p re s e rv a tio n o f fo o d
Early in v e n tio n s
1795
•
French government needs supply of preserved food to feed the nation’s
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