Jun 22 min read

Preservative or Problem: Understanding Lantibiotics

Fairfax, VA

We’ve all heard the joke about how the Twinkies at your local supermarket could survive a nuclear war--or at least a few decades. It is more than common to have such stores filled with rows and rows of processed food. This processed nature of certain products allows them to last longer, as manufacturers will often add preservatives into the product in the process--the same preservatives that keep those Twinkies long-lasting. However, contrary to common thought, such preservatives actually aren’t often artificial in nature. In an attempt to keep the products’ required lists of ingredients free from the names of such artificial preservatives, natural preservatives are often used instead, and this more natural source can be preferable for many customers.

Such natural preservatives aren’t necessarily the olden days’ choice of large quantities of salt. Microbes present themselves as a convenient source of natural preservatives, with certain bacteria producing products termed bacteriocins as defense mechanisms to harm other bacteria. Thus, the bacteriocins, and more specifically the stronger ones in the Lantipeptides subcategory, can be used to stop pathogens (ex: gram-positive bacteria or bacteria with thick cell peptidoglycan walls) from developing in processed foods over time. These microbial products have been termed as “lantibiotics,” and their lack of toxicity to humans and animals have made them convenient for wide use by manufacturers.

cheese nisin fondue food chips gut health lantibiotic — Cheese fondue, a type of cheese product

However, a lack of toxicity isn’t equivalent to no effects. Dr. Zhang and many researchers associated with either the University of Chicago or University of Urbana-Champaign asked the question: if such lantibiotics hold properties to harm other bacteria, how exactly do they affect the commensal bacteria inside our gut microbiome? To take a closer look at this concern, the researchers looked at a commonly used lantibiotic, nisin A, part of a group of class I lantibiotics and created by the bacterium Lactococcus lacti. Nisin A in particular is used in a variety of cheeses, meats, and canned foods. By running antimicrobial assays for nisin A and other class I lantibiotics similar to it, the researchers were able to determine that mildly inhibitory (and thus, detrimental) effects were found on commensal bacteria of the gut microbiome. This result indicates that eating food involving such lantibiotics, used as natural preservatives, may cause not so positive effects on the gut microbiome--though further testing is needed on the matter.

The gut microbiome may appear to simply be involved in nutrient metabolism, contributing to the breakdown of food. However, this complex community of many bacterial species pitch in both with individual roles and in broader roles resulting from communal interactions in areas ranging from one’s immune system to their mood (through the gut-brain axis). Thus, effects on the gut microbiome, which is strongly influenced by the person’s environment and the food they intake, are important to a person’s health. By understanding the effect of such lantibiotics and their use in the food the majority of people partake in, research and measures can be taken to improve food preservatives and provide healthier options if necessary.