Entertainment · August 4, 2022

A smartphone app could alert you to cancer-causing chemicals in meat

A new smartphone app could warn users about cancer-causing chemicals in processed meats like sausages, ham, bacon and salami.

Scientists in Spain have developed a system that includes a color-changing film called “POLYSEN” that consumers can stick onto meat products.

Labels darken when they detect high levels of nitrite — a meat preservative that can form potentially carcinogenic compounds.

Users can then photograph the foil with their smartphone, a specially developed app analyzes the color and gives a value for the nitrite concentration.

Cured and processed meats, such as salami and bacon, are often treated with nitrite or nitrate salts to keep them looking and tasting fresh (file photo)

Graphic from the researchers' paper shows how the system works.  Discs punched out of the foil are placed on meat samples for 15 minutes to allow them to react with nitrite.  The disks are then removed and immersed in a sodium hydroxide solution for one minute to develop the color.  The more nitrite present, the deeper the yellowish hue of the film.  A smartphone app calibrates itself when a chart of reference slices is photographed in the same image

Graphic from the researchers’ paper shows how the system works. Discs punched out of the foil are placed on meat samples for 15 minutes to allow them to react with nitrite. The disks are then removed and immersed in a sodium hydroxide solution for one minute to develop the color. The more nitrite present, the deeper the yellowish hue of the film. A smartphone app calibrates itself when a chart of reference slices is photographed in the same image

HOW DOES “POLYSEN” WORK?

POLYSEN or “polymeric sensor” is a film made from four monomers and hydrochloric acid.

Discs punched out of the foil are placed on meat samples for 15 minutes to allow them to react with nitrite.

The disks are then removed and immersed in a sodium hydroxide solution for one minute to develop the color.

The more nitrite present, the deeper the yellowish hue of the film.

A smartphone app calibrates itself when a chart of reference slices is photographed in the same image.

The system was developed by experts at the Universidad de Burgos in Spain and is detailed in a new study published in ACS Applied Materials & Interfaces.

“There is a need to identify and control various chemical compounds that are added to processed foods such as processed meat,” they say.

“Our method represents a major advance in terms of analysis time, simplicity and orientation for use by the average person.”

Cured and processed meats like bacon, hot dogs, ham, and sausages (including mortadella, an Italian breakfast meat) are often treated with nitrite or nitrate to keep them looking and tasting fresh.

Nitrites are commonly used in processed meats to extend their shelf life by fighting off bacteria that can cause diseases like salmonella, listeriosis, and botulism.

Crucially, they also add an alluringly tangy flavor and pink hue to products like bacon, making them appear more appetizing.

Although nitrate is relatively stable, it can be converted to the more reactive nitrate ion in the body.

In the acidic environment of the stomach or under the high heat of a frying pan, nitrite can react to form nitrosamines, which have been linked to the development of various types of cancer.

Because of this, consumers want to limit their consumption of these preservatives, but it has been difficult to know how much is in a food.

Nitrites give products like sausages, ham, bacon and salami an enticingly spicy flavor and an enticingly fresh pink hue (file photo).

Nitrites give products like sausages, ham, bacon and salami an enticingly spicy flavor and an enticingly fresh pink hue (file photo).

Here, a worker packs slices of mortadella, an Italian luncheon meat, at a factory (file photo)

Here, a worker packs slices of mortadella, an Italian luncheon meat, at a factory (file photo)

So the researchers made the new POLYSEN film – an abbreviation for “polymeric sensor” – which consists of four monomers and hydrochloric acid.

To create a ‘reference chart’, discs punched out of the foil were first placed on five different meat samples for 15 minutes to allow the monomer units and acid in the foil to react with nitrite.

The meat samples all had different levels of nitrite, so the researchers knew the slices would vary in color.

The disks were then removed and immersed in a sodium hydroxide solution for one minute to develop the color.

The higher the level of nitrite present in the meat, the deeper the yellowish hue of each film became.

To calibrate the system, discs punched out of the foil were placed on five different meat samples for 15 minutes, allowing the monomer units and acid in the foil to react with nitrite

To calibrate the system, discs punched out of the foil were placed on five different meat samples for 15 minutes, allowing the monomer units and acid in the foil to react with nitrite

Next, the researchers created the smartphone app that uses colorimetry – which uses light to determine the concentration of specific compounds.

When photographed in the same image as the reference map, the app can return a nitrite estimate for the sample disk.

The team tested the film on home-prepared and nitrite-treated meat in addition to store-bought meat.

They found that the POLYSEN-based method gave results similar to a traditional and more complex nitrite detection method.

In addition, POLYSEN complies with a European regulation on the transfer of substances from the film to the food.

While the team has only demonstrated the system so far, in the future it could offer consumers a user-friendly and inexpensive way to determine nitrite levels in food.

‘This study is intended to serve as a proof of concept, showing that the methodology is practical and works,’ they conclude.

NITRITES AND NITRATES: ONE PRIMER

Nitrite and nitrate are commonly used in curing meat and other perishable products.

They are also added to meat to keep it red and add flavor.

Nitrate also occurs naturally in vegetables, with the highest levels found in leafy greens like spinach and lettuce.

It can also enter the food chain as an aquatic environmental pollutant due to its use in intensive agriculture, livestock farming and wastewater discharge.

Nitrite in food (and nitrate, which is converted to nitrite in the body) can contribute to the formation of a group of compounds known as nitrosamines, some of which are carcinogenic, meaning they have the potential to cause cancer.

In 2015, the World Health Organization warned of a significant increase in colon cancer risk from eating processed meats like bacon, which traditionally have nitrites added during curing.

According to the European Food Safety Authority (EFSA), the currently acceptable daily dose for nitrates is 3.7 milligrams per kilogram of body weight per day.

The EFSA acceptable daily allowance for nitrites is 0.07 mg per kilogram of body weight per day.

Source: EFSA