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Model predicts Listeria’s survival skills
Extracts offer natural antimicrobial action
Diet firm Atkins launches super premium ice cream
Personality improves with age, says study
Hershey breaks ground in Illinois
Food safety
Model
predicts Listeria’s survival skills
US researchers have built a model
to help food processors take into account the Listeria bacterium’s
ability to evolve an ability to survive increasingly high temperatures.
Because bacteria can’t run away,
they have developed coping mechanisms that allow them to adapt to hostile
environments, says Aubrey Mendonca, a Food Safety Consortium researcher at
Iowa State University.
“Bacteria have quick genetic
switches so that they can produce things called stress proteins. So while
they are starving, they produce stress proteins that make them stronger
than in that starved state. They are not strong enough to multiply, but
they are not going to go away."
The bacteria in processing plants
emerge in a hostile environment of dust, dirt and water condensing behind
coolers, Mendonca said. Back in the lab, conditions aren't so rugged.
"Microbiologists tend to grow organisms in rich media and use them in
experiments. But are those organisms in the laboratory representative of
the same organisms coming out the factory environment? No."
Mendonca's experiments show that
organisms starved under lab conditions produce offspring that are more
resistant to heat when they are placed in meat. For food processors, this
means bacteria that survive cleaning and sanitation may remain without
nutrients on food contact surfaces and develop heat resistance.
Mendonca's model of the
heat-resistant capacities of Listeria monocytogenes also shows the
use of salt and sodium pyrophosphate in meat can sometimes help Listeria
monocytogenes to survive. "If I have a product with a high salt level
and another with a low salt level and I heat them equally, the product
with the high salt level may need a little more heat to kill the bacteria
because there is less water available," Mendonca said. This is
because heat works best when more moisture is available. An increase in
salt causes a decrease in the amount of free water in the product, so more
heat is needed to make up for the deficiency and kill the pathogens.
Processors may still be able to use
the models developed in less stringent laboratory conditions and still
avoid resurgence of the bacteria during heating if their numbers of
pathogens are consistently low. "But if the numbers get high enough,
you're going to run into a problem," he warned.
Extracts
offer natural antimicrobial action
Edible films made from natural
extracts can extend shelf life, adding colour and enhancing freshness,
according to new research.
Top extracts include black tea and
grape seeds. All the processors need to do is work the extract into an
invisible edible film on the food surfaces.
"We are incorporating these
extracts that have excellent antimicrobial activities into the edible
films," said Navam Hettiarachchy, a University of Arkansas food
science professor who is leading a research project on the topic for the
Food Safety Consortium. "We are going to use these in food products
such as poultry, sausage, meat and minimally processed fresh-cut fruits
and vegetables as a dip or spray."
Hettiarachchy's team found that
black tea hot water extract prevented growth of Listeria monocytogenes.
Grape seed extract was effective in inhibiting Salmonella typhimurium
and E. coli O157:H7. These two were the most successful against
pathogens among several extracts screened from plants, herbals,
vegetables, beans, grains and bran. The extracts were incorporated into
several edible films, including soy protein, whey protein, gluten protein,
carboxymethyl cellulose, carageenan and pectin, ands applied to food
products by spray, dip and wrap. This can extend the products’ shelf
life for about two weeks. "Also, these extracts serve as antioxidants
because when you keep the meat for a long time, it becomes rancid,"
Hettiarachchy said. "The extracts prevent rancidity and kill or
minimise the pathogens."
The edible film coating can also
delay the ripening of tomatoes by two to three weeks. "You can keep
the freshness of baby carrots, which usually dry up. The coating keeps the
colour and the crunchiness for longer."
The edible films in these
experiments use malic acid, an organic acid that occurs in apples.
"Consumers are used to eating apples that contain malic acid,"
Hettiarachchy said. "So when you incorporate the malic acid in the
film-forming solution, it not only has the effect as an antimicrobial, it
also acts as a plasticiser." The plasticiser makes the film more
flexible.
That flexibility is helpful when
the film is used to coat egg shells. Hettiarachchy explained that the
flexibility prevents breakage of the eggs during transit, which currently
averages 10% but could be reduced to 2% with this innovation.
Egg shells are also less
susceptible to Salmonella when they are coated with the extracts'
film. Hettiarachchy hopes to commercialise the
patented films in a year's time.
NPD/Launch
Diet firm Atkins
launches super premium ice cream
An ice cream with only 30% of the
carbohydrates of normal super premium ice creams has emerged from Atkins
Nutritionals, the company started by the man who developed the popular
Atkins diet.
The sugar-free ice cream, Atkins
Endulge, comes in chocolate and vanilla flavours and contains only 4 g of
Net Carbs, carbohydrates that affect blood sugar, per 4 oz (112 g)
serving. But it contains 16% butterfat, putting it into the super premium
category. To remind people to avoid binging and over-indulging, the ice
cream is packaged in portion-controlled 4-ounce cups, four cups to a
container.
Mister Cookie Face, a family
business in Lakewood, New Jersey that makes ice cream novelties sold
nationally, produces the ice cream.
Consumers
Personality
improves with age, says study
People become nicer and more
conscientious as they grow older, recent US research results indicate.
Rather than a decline, ageing means becoming more agreeable and open and
less neurotic.
The findings from Stanford
University challenge the usual view
that personality traits are
programmed genetically to stop changing by early adulthood, meaning that
personalities are fully formed by the time people reach their 30s.
The researchers compared the
personalities of 132,515 adults between the ages of 21 and 60 who
completed an Internet personality test. The participants took the Big Five
Inventory. These test conscientiousness, agreeableness, neuroticism,
openness and extraversion.
The survey showed that
conscientiousness increased with age, with people in their 20s showing the
biggest improvements in discipline and organisation skills. Agreeableness
also climbed with age, largely among thirty-somethings.
Men and women differed in their
relative neuroticism. As women aged, their neurotic tendencies declined,
but this was not the case for men. Openness waned slightly for both sexes,
as did extraversion in women.
“The changes in conscientiousness
and agreeableness line up with when people increase their work
responsibilities and when they have kids,” said researcher Sanjay
Srivastava. “All the biggest changes were for the better.”
Business
Hershey breaks ground in
Illinois
US chocolate maker Hershey Foods is
to build a new distribution centre in the Gateway Commerce Center in
Madison County, Illinois. The 1.1 million-square-foot (102,000 square
metre) centre should open by March 2004 on the 90 acre (36.4 hectare)
plot.
Hershey's Midwest distribution
centre features a 10 metre ceiling, 160 dock doors, and full temperature
control. It is the company's fourth high-performance warehouse aimed to
improve customer service and implement a low-cost supply chain. The other
centres are located in Hershey, Pa, Atlanta, Ga, and Redlands, Calif.
Genco Distribution System will run
the facility and will employ more than 200. |
