For thousands of years, humans have . As the name implies, the bacterium is a milk lover and thrives on milk’s primary sugar, lactose. It also is involved in the fermentation of milk products, a practice known to help keep the dairy products over time.
Research into how this bacterium can help preserve food has revealed it sends out into the environment an effective bacteria-killing molecule known as nisin. It’s a powerful food preservative and has the ability to deal with Listeria. For the authors, this species was the perfect base to conduct their assessment.
Before performing the tests, the team wanted to give the lactis bacteria a little more killing power as some studies have suggested Listeria can persist in the presence of nisin. The group gave the good bacteria the ability to produce another Listeria-defeating molecule known as leucocin-C. The hope was to see a one-two punch to the pathogen such that it would not be able to survive.
The new, stronger lactis strain was allowed to grow in a liquid for about 8 hours. During this time, the individual cells produced nisin and leucocin-C and sent them out into the environment as usual. At the end of the growth time, the liquid – now filled with these killing molecules – was separated from the bacteria.
The team put the liquid into cultures of Listeria as well as a number of other pathogens such as Escherichia coli O157:H7 and Salmonella. The hope was to see a decent reduction if not total kill. Everything went as expected as the pathogens were easily reduced in number and in some cases, eliminated.
It will be some time before we see bacteria-preserved milk
This set the stage for the ultimate test. The lactis liquid was placed into pasteurized milk containing Listeria and a very small amount of a preservative known simply as EDTA. Once again, it all went according to plan. The levels of Listeria dropped significantly within the first hours and stayed that way for at least a day.
For the authors, this concept of using bacteria to fight bacteria offers a new direction in helping to preserve milk and other dairy products after pasteurization. By keeping the food free of pathogens such as Listeria, the entire food production chain can be considered safer. This could help to reduced numbers of infections and …
Source:: The Huffington Post – Canada Travel