Bacterium May Improve Food Security

ROTTEN VEGETABLES

There’s nothing worse than discovering rotten food. The once perfect source of nourishment has transformed into a stinking, discoloured shell of its former self and is relegated to the trash bin or the organic recycling container.

For most of us, this phenomenon simply means a trip back to the grocery store to restore supplies. But in many parts of the world, spoilage is a much greater problem.

Based on information from the Rockefeller Foundation, about 1/3 of all food is wasted as a result of spoilage. Finding solutions to this could improve the quality of life for about a billion people worldwide. It could also help reduce the prices of these food items and at the same time help to keep more money in our pockets.

Providing solutions has been difficult. Some of the original ideas, such as pesticides have been regarded as anathema. Another concept that was once hailed which involves the use of irradiation, has only limited value, as equipment is not universally available and the cost can be quite high. Another option was antimicrobial, however, the use of this technique requires specialized labs to make the effective preservatives and it is very expensive to bear.

In the wild, a variety of species roam effortlessly searching for the next place to thrive. For them, vegetables and fruit are the perfect residence. When they connect, they begin a common process of growth and spread. The result is a large microbial mass called a biofilm. As the microbes continue to grow, they break down the cellular matrix of the food, causing it to turn colour and eventually degrade to slime. Also, as the bacteria feed, they release waste, which can sometimes be noxious to our sensitive nostrils. Within a few days, the once-beautiful food becomes nothing more than a mess.

In reducing spoilage, microbes were discovered to preserve foods and ensure a longer shelf life at a reasonable cost. Using bacteria to preserve foods has been around for millennia in the guise of fermentation. This practice has been forgotten thanks to refrigeration and chemical preservatives. Yet, in many countries of the world, this routine continues to be one of the best ways to keep food fresh.

The fermentation procedure is essentially the same. A bacterial mix -sometimes called a starter culture – is added to foods usually in water or some other liquid. Over time, the bacteria change the nature of the food, adding acidity and a host of antimicrobial compounds. This helps to prevent spoiling bacteria from growing. After few hours, days, weeks, or in some cases months, the food is kept fresh and can be enjoyed far later than the usual shelf life.

There is however a requirement with traditional fermentation, preventing it from being used en masse for food security. It has to be performed in batches. This significantly reduces the flow of the food continuum and potentially leaves valuable food resources left to spoil while it waits. The process can be upscaled but can never reach the volume needed to save billions of people.

In proffering solution to this, recently a team of scientist from Malaysia introduced a fermenting bacterium with the ability to protect food without the need for batches. Based on the results of the study, in the future, all that may be needed is a quick spray and the food would be safe from microbial spoilers.

The scientist decided not to look at fermentation starter cultures but instead look at plants known to resist spoiling in the wild. They looked at the bacterial population of one plant, pandan, which is used in Asian cuisine. They found quite a number of different species, many of which are known fermenters. But amongst the population, they found one that was quite unique, in that it acted just like a spoiler without the drastic consequences.

The strain is called Lactobacillus plantarum PA21 and in the lab, it did not only grew like all other bacteria, but formed biofilms. This was both new for this bacterium and also opened the door to a novel idea. The bacterium could create a barrier on fruits and vegetables to block out spoiling species. When tested in the lab, it was discovered that biofilms grew quite well in temperatures similar to that of the Malaysian climate.
This was only half the goal.

The next step was to introduce various species of bacteria to see if the good biofilms would hold strong. Compared to controls without biofilms, the results were dramatic. The spoiling bacteria were either completely eliminated or reduced significantly to safe levels. In essence, at least in the lab, the results provided the promise for future preservation.

While this information was already positive, the scientist hinted it could get better. They attempted to put other factors into the bacterium using genetic modification. They were successful suggesting other preservative factors, such as antimicrobials which could one day be introduced to make them even more powerful.

In the context of food security, the team suggested Lactobacillus plantarum PA21 represents a bright future. The bacterium is easy and inexpensive to grow, can be manipulated genetically, and also can be used worldwide as it has no pathogenic properties. With further testing, the perfect microbial preserver may be developed and then eventually mass produced. If all goes well, it may one day end up not only on crops in countries suffering from food shortages, but perhaps even our local grocery store.