Stopping listeria reproduction 'in its tracks'
Researchers discover CoO-TiO2 compound to mitigate bacterial
contamination

Date:
July 27, 2020
Source:
University of Houston
Summary:
Listeria contaminations can send food processing facilities into
full crisis mode with mass product recalls, federal warnings
and even hospitalization or death for people who consume the
contaminated products. Researchers have discovered a chemical
compound that stops listeria reproduction in both light and dark
conditions which could lead to bacterial control in food products.



FULL STORY ========================================================================== Listeria contaminations can send food processing facilities into full
crisis mode with mass product recalls, federal warnings and even hospitalization or death for people who consume the contaminated
products. Destroying the bacterium and stopping its spread can be
challenging because of the formation of biofilms, or communities of
resistant bacteria that adhere to drains or other surfaces.


========================================================================== Researchers at the University of Houston are reporting in the Journal
of Environmental Chemical Engineering that cobalt-doped titanium-dioxide
(CoO- TiO2) stops the reproduction of listeria monocytogenes in both light
and dark conditions. This bacteriostatic effect could lead to bacterial
control in food products that are not only sealed but also protected
from light such as tetra packs, cans and dark glass or plastic bottles.

"The addition of cobalt, a heavy metal, drastically improved the
effectiveness of titanium-dioxide because now it works under regular
human conditions - - sunlight, fluorescent light such as light bulbs
and even in 'the absence of light,' like in a freezer," said Francisco
Robles, lead author for the study and associate professor of mechanical engineering technology.

Titanium-dioxide has long been an effective catalyst in the chemical
industry with many applications, but it has limitations because
ultraviolet light is needed to make it work, according to Robles. "UV
light sources are in short supply in sunlight and producing it is
expensive and a health hazard (e.g.

carcinogen), so we set out to find a solution. Making it effective under natural light conditions is significant, and free," he said.

A naturally occurring mineral, titanium-dioxide is often used in the
food industry as an additive or whitening agent for sauces, dressings
and powdered foods and is considered safe by the U.S. Food and Drug Administration. It's also used in sunscreen for its protective effects
against UV/UVB rays from the sun.

Sujata Sirsat, study co-author and assistant professor at UH's
Conrad N. Hilton College of Hotel and Restaurant Management, believes cobalt-doped titanium- dioxide, whether manufactured directly into food packaging or added to food products, could potentially reduce the risk
for large listeria outbreaks in food processing environments.

"Listeria is a rare foodborne pathogen that can survive in refrigerated conditions. So, if you had a contaminated bowl of potato salad, not only
can listeria survive, it can increase in numbers potentially causing a
serious health issue. The cobalt-doped titanium dioxide can potentially
stop the spread in its tracks," said Sirsat, an expert in food safety
and public health, who said toxicity testing is needed to determine its
safety in food products.

An estimated 1,600 people get listeriosis each year from eating foods contaminated with listeria monocytogenes, and about 260 people die,
according to the U.S. Centers for Disease Control and Prevention. The
CDC has led investigations on 19 multistate listeria monocytogenes
outbreaks involving fruits, vegetables, deli meats, cheeses and more
since 2011. The infection is most likely to sicken pregnant women and
their newborns, adults over 65 and people with weakened immune systems.

The researchers believe cobalt-doped titanium-dioxide could have a wide
range of applications beyond bacteria control. "You could coat hospital
plates with it to make them incapable of forming bacteria or coat the
packaging of milk and other dairy products. You could even add it to paint
to make bacteria- controlled paint. The possibilities are tremendous,"
said Robles, who has been studying the effects of the chemical compound
for nearly 15 years.


========================================================================== Story Source: Materials provided by University_of_Houston. Original
written by Chris Stipes.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Sujata A. Sirsat, Oscar Hecht, Carlos Mirabal, David A. Pepe,
Wenli Yang,
Zahra Mohammad, Viktor G. Hadjiev, Jack A. Neal, Francisco
C. Robles Hernandez. Bacteriostatic Effect of CoO-TiO2 on
Listeria Monocytogenes by the Presence of the Co-Catalytic CoO
Nanoparticles. Journal of Environmental Chemical Engineering,
2020; 104259 DOI: 10.1016/ j.jece.2020.104259 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200727145810.htm

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