Most people are used to thinking of bacteria and food as a bad combination. After all, pathogenic bacteria are well-known for their role in spoiling food and spreading dangerous foodborne illnesses. But did you know that, when chosen and employed properly, some bacteria can actually help preserve food?
Welcome to the world of biopreservation: a method of preserving food that involves the manipulation of microbial organisms, including certain types of bacteria. Biopreservation has been used in food preparation for thousands of years.
This preservation method is currently having a moment in the spotlight. More and more food manufacturers are searching for ways to keep food fresh and safe without relying on synthetic additives. Read on to learn more about biopreservation, how it works, and where it’s headed in today’s food industry.
What is biopreservation?
In order to prevent food from going bad or making us sick, food manufacturers must add antimicrobials to their products. These important additives destroy or inhibit the growth of pathogenic bacteria and other spoilage microorganisms. This extends the shelf life of food and allows it to be safely consumed over a longer period of time.
Many antimicrobials used in the food industry are synthetically produced. However, there are a number of plant- and bacteria-based antimicrobials that can serve as viable natural alternatives. These microorganisms produce certain compounds, including acid and small antimicrobial peptides known as bacteriocins, that work against the harmful bacteria in food. When these naturally-occurring microorganisms, or the compounds they produce, are used to preserve food, this is known as biopreservation.
What are some examples of biopreservation?
There are several different forms of biopreservation. The choice of method depends on a variety of factors, including the type of food to be preserved, its pH, and the harmful bacteria that need to be inhibited.
One form involves adding the natural antimicrobial microorganisms themselves directly to the food product. Once added, they will produce the necessary acids and inhibitory compounds by feeding off the carbohydrates and other nutrients present in the food.
Fermentation is another commonly used biopreservation option. In this case, the microorganisms are added to a nutrient solution, such as milk or sugar water, and are allowed to grow and produce inhibitory compounds in this solution. The entire solution is then added to the food product.
This biopreservation method is effective because the inhibitory compounds have the opportunity to grow before they are added to the food to be preserved. This is unlike the first method described, in which the metabolites must build up over time as the microorganisms grow in the food.
Finally, it is possible to add either a partially purified mixture (an antimicrobial with a higher concentration of inhibitory compounds), or a purified bacteriocin to foods for preservation. However, these options are more expensive than the two others described above, so they are not used as often by the food industry.
All of these antimicrobial microorganisms can come from different sources, and are each suited for use in different food products. Some of the microorganisms that are currently available as commercial products include live cultures of lactic acid bacteria and the bacteria known as carnobacterium maltaromaticum; a basic fermentate of pediococcus (a type of lactic acid bacteria that includes two bacteriocins); and a partially purified antimicrobial whose active component is natamycin (this helps prevent the development of spoilage mold on the surface of baked goods).
Why are so many food industry players focusing on biopreservation today?
It’s not surprising that biopreservation is a trending topic in the food industry given the strong consumer preference for foods that are free from synthetic ingredients. Today’s consumers are increasingly insisting that, whenever possible, food manufacturers use natural versions of common additives, including preservatives, colors, and other ingredients.
This rapidly-growing consumer movement has the food industry as a whole re-examining its use of synthetic additives and exploring a broad range of natural alternatives, such as biopreservation.
What issues or challenges are associated with biopreservation?
While biopreservation offers manufacturers an effective way to preserve food naturally, this method is not without its own challenges. For example, antimicrobials that are derived from plant sources often have a very strong flavor and/or aroma. This could have a negative impact on the taste or smell of foods to which it is added.
In addition, some plant extracts must be used in very high concentrations in order to be effective antimicrobials. This makes them more costly. It could also lead to potential toxicity issues.
What does the future hold for biopreservation?
Research is currently underway to find new sources of biopreservative products. Prospects include microorganisms derived from soil or animals rather than fermentation or food isolates. Some labs are also experimenting with different culture combinations or purified antimicrobials to create blends that are optimized for effectiveness.
While all this research is promising, it’s important to remember that it can take a long time for new products to journey from the lab to the marketplace. Extensive tests for safety are needed to determine if the product is appropriate for use in food, and comprehensive analyses are required to establish if the product can economically be used in commercial food production.