SPAGYRIC HERBALISM
Natural shield: Licorice extract keeps ready-to-eat chicken safer and longer
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Licorice extract significantly inhibited Paraclostridium bifermentans spore growth in ready-to-eat chicken breast, with enhanced effects at higher concentrations. Growth curves (15, 20, and 25 °C) fitted well with Gompertz and Logistic models (R² > 0.98), aiding critical control point identification for industrial processing. The extract also preserved meat color, reduced pH, and suppressed thiobarbituric acid reactive substances (TBARS) value and total volatile basic nitrogen (TVB-N) content increases, demonstrating its potential as a natural antimicrobial for shelf-life extension.
view moreCredit: Food Science of Animal Products, Tsinghua University Press
Ready-to-eat (RTE) chicken breast is increasingly popular for its high protein content and convenience, but its moist and nutrient-rich environment makes it a perfect breeding ground for spoilage bacteria. One of the most stubborn threats is Paraclostridium bifermentans, a spore-forming bacterium that survives heat processing and flourishes under improper storage. Traditional chemical preservatives are effective, yet growing concerns about toxicity and consumer preference for “clean label” foods drive the search for safer alternatives. Natural preservatives, especially those derived from plants, offer promise. Given these challenges, further investigation into the antibacterial potential of licorice extract in RTE meat products is both timely and essential.
In a recent study (DOI: 10.26599/FSAP.2025.9240115) published on March 24, 2025, in Food Science of Animal Products, a team from Nanjing Agricultural University explored how licorice extract affects bacterial spore growth and meat quality in RTE chicken breast. By combining microbiological assays with mathematical growth models, the researchers tested different storage temperatures and extract concentrations to evaluate both microbial inhibition and product freshness. Their findings mark a significant step toward replacing synthetic preservatives with natural, plant-based solutions.
The team began by treating chicken breast samples with varying concentrations of licorice extract and exposing them to P. bifermentans spores. They found that extracts at 12.5 mg/mL or higher significantly curbed spore growth, with 50 mg/mL proving most effective—doubling shelf life at 15 and 20 °C. Using Gompertz and Logistic models, the researchers mapped spore growth curves, revealing high accuracy (R² > 0.98) in predicting microbial dynamics. The Ratkowsky model further clarified how temperature influences bacterial lag phases and growth rates. In addition to suppressing bacterial growth, licorice extract helped preserve the meat’s physical and chemical qualities: treated samples exhibited lower pH, TBARS (an indicator of fat oxidation), and TVB-N (a marker for protein degradation). Even after extended storage, color and surface texture remained acceptable. These results suggest that licorice extract not only prevents microbial spoilage but also maintains overall meat quality—crucial for consumer acceptance and food safety.
“Licorice extract demonstrates strong antimicrobial properties against one of the most resilient spoilage organisms in meat,” said Prof. Ming Huang, the study’s corresponding author. “By combining traditional botanical knowledge with modern food modeling techniques, we’ve shown a practical way to enhance meat safety without resorting to synthetic chemicals. This work provides a solid scientific foundation for incorporating natural preservatives into commercial meat products.”
The implications of this research extend well beyond a single product. Incorporating licorice extract into RTE meat processing could offer manufacturers a natural alternative to synthetic preservatives, appealing to health-conscious consumers and reducing food waste. The predictive models developed in the study can also serve as tools for optimizing storage conditions and setting microbial safety thresholds. As the food industry shifts toward more sustainable and transparent production methods, licorice extract—once known mainly for its flavor—may emerge as a key player in the future of clean-label food preservation.
This study was supported by the National Key R&D Program of China (2024YFD2100404), Key Research and Development Program of Shandong Province (2023TZXD035), High-Level Talent Introduction Program of Henan University of Technology (2025BS002), the Program of Taishan Industry Leading Talents and Agriculture Research System of China (CARS-41-Z).
Journal
Food Science of Animal Products
Article Title
Effects of licorice extract on Paraclostridium bifermentans spore growth and quality changes in ready-to-eat chicken breast during storage
Maple compound offers new way to fight tooth decay
American Society for Microbiology
Washington, D.C. — A new study in the journal Microbiology Spectrum highlights the potential of using a natural compound from maple to combat the bacteria responsible for tooth decay: Streptococcus mutans. The compound, epicatechin gallate, is a powerful and safe alternative to traditional plaque-fighting agents. Its natural abundance, affordability and lack of toxicity make it especially promising for inclusion in oral care products such as mouthwashes, offering a safer option for young children, who often accidentally swallow mouthwash.
The new study emerged as an offshoot of research into natural compounds that inhibit biofilm formation in Listeria monocytogenes, a foodborne pathogen. As is often the case in science, the researchers made an unexpected observation that Listeria readily forms biofilms on plant materials, including most wood, but seems to avoid certain types, especially maple. This piqued the researchers’ curiosity. They isolated polyphenolic compounds from maple that inhibit Listeria attachment and biofilm formation. They also identified their target: sortase A, an enzyme that anchors adhesins to the bacterial cell wall. When sortase A is inhibited, these adhesins are not anchored in the bacterial cell wall, impairing the ability of Listeria to attach to surfaces and form biofilms. That discovery led the researchers to investigate whether similar mechanisms exist in related bacteria. Sortase A in Streptococcus species, which is Listeria’s cousin in the Bacillota phylum, turned out to be quite similar. One species in particular, Streptococcus mutans, stood out because it causes dental caries, commonly known as cavities.
“Since S. mutans initiates cavities by forming biofilms (plaques) on teeth and producing acid that destroys tooth enamel, we asked: could maple polyphenols also inhibit S. mutans biofilms? That question drove this study,” said corresponding study author Mark Gomelsky, Ph.D., Martha Gilliam Professor of Microbiology and Director of the Microbiology Program at the University of Wyoming.
The researchers first used computer modeling to see whether maple polyphenols could bind to the sortase A enzyme from S. mutans, and discovered that they did. Next, they purified the sortase A in the lab and confirmed that these compounds inhibit its activity in a test tube. Finally, they assessed whether maple polyphenols block S. mutans from forming biofilms on plastic teeth and on hydroxyapatite disks—a stand-in for real tooth enamel— and discovered they worked there too.
“In a way, this study felt almost too easy. Everything fell into place just as we predicted. That’s a rare experience in science, and probably the first time it’s happened in my 35-year research career,” Gomelsky said. “We discovered that several polyphenols present in maple wood or maple sap can inhibit the sortase enzyme in S. mutans, which in turn prevents this cavity-causing bacterium from attaching to tooth surfaces.” Interestingly, the most potent inhibitor was (-)-epicatechin gallate (ECG), a compound also present in green and black tea, though in much higher amounts in tea than in maple sap. Drinking green tea has long been associated with lower rates of cavities, and its main polyphenol, (-)-epigallocatechin gallate (EGCG), has been used in dental products. The researchers found that EGCG does inhibit S. mutans biofilms, but it’s not nearly as effective as ECG. This raises the intriguing possibility that the moderate effects seen with EGCG-based dental products may be due to using the suboptimal compound, instead of the more potent ECG.
“Our findings suggest that ECG or other edible polyphenols with anti-sortase activity could be added to dental products to help prevent cavities through an antibiofilm mechanism,” Gomelsky said. “This is different from traditional approaches, which rely on killing bacteria with alcohol, disinfectants or essential oils, or on fluoride to remineralize enamel. The antibiofilm approach using edible polyphenols is especially appealing for young children. For example, young children can’t use conventional mouthwashes because they might swallow them and risk toxicity. A safer alternative, such as a mouthwash containing an effective dose of an edible polyphenol, could provide protection without harmful side effects.”
Gomelsky said they are actively developing plant polyphenol-based dental products through a startup founded by University of Wyoming students and the first author of this study, Ahmed Elbakush, Ph.D.
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The American Society for Microbiology is one of the largest professional societies dedicated to the life sciences and is composed of over 37,000 scientists and health practitioners. ASM's mission is to promote and advance the microbial sciences.
ASM advances the microbial sciences through conferences, publications, certifications, educational opportunities and advocacy efforts. It enhances laboratory capacity around the globe through training and resources. It provides a network for scientists in academia, industry and clinical settings. Additionally, ASM promotes a deeper understanding of the microbial sciences to all audiences.
Journal
Microbiology Spectrum
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