Anti-listerial synergism of leaf essential oil of Metasequoia glyptostroboides with nisin in whole, low and skim milks

Essential Oils and Their Combination with Lactic Acid Bacteria and Bacteriocins to Improve the Safety and Shelf Life of Foods: A Review

The use of plant extracts (e.g., essential oils and their active compounds) represents an interesting alternative to chemical additives and preservatives applied to delay the alteration and oxidation of foods during their storage. Essential oils (EO) are nowadays considered valuable sources of food preservatives as they provide a healthier alternative to synthetic chemicals while serving the same purpose without affecting food quality parameters. The natural antimicrobial molecules found in medicinal plants represent a possible solution against drug-resistant bacteria, which represent a global health problem, especially for foodborne infections. Several solutions related to their application on food have been described, such as incorporation in active packaging or edible film and direct encapsulation. However, the use of bioactive concentrations of plant derivatives may negatively impact the sensorial characteristics of the final product, and to solve this problem, their application has been proposed in combination with other hurdles, including biocontrol agents. Biocontrol agents are microbial cultures capable of producing natural antimicrobials, including bacteriocins, organic acids, volatile organic compounds, and hydrolytic enzymes. The major effect of bacteriocins or bacteriocin-producing LAB (lactic acid bacteria) on food is obtained when their use is combined with other preservation methods. The combined use of EOs and biocontrol agents in fruit and vegetables, meat, and dairy products is becoming more and more important due to growing concerns about potentially dangerous and toxic synthetic additives. The combination of these two hurdles can improve the safety and shelf life (inactivation of spoilage or pathogenic microorganisms) of the final products while maintaining or stabilizing their sensory and nutritional quality. This review critically describes and collects the most updated works regarding the application of EOs in different food sectors and their combination with biocontrol agents and bacteriocins.

Combined antimicrobial effect of bacteriocins with other hurdles of physicochemic and microbiome to prolong shelf life of food: A review

Bacteriocins are ribosomally synthesized peptides to inhibit food spoilage bacteria, which are widely used as a kind of food biopreservation. The role of bacteriocins in therapeutics and food industries has received increasing attention across a number of disciplines in recent years. Despite their advantages as alternative therapeutics over existing strategies, the application of bacteriocins suffers from shortcomings such as the high isolation and purification cost, narrow spectrum of activity, low stability and solubility and easy enzymatic degradation. Previous studies have studied the synergistic or additive effects of bacteriocins when used in combination with other hurdles including physics, chemicals, and microbes. These combined treatments reduce the adverse effects of chemical additives, extending the shelf life of food products while guaranteeing food quality. This review highlights the advantages and disadvantages of bacteriocins in food preservation. It then reviews the combined effect and mechanism of different hurdles and bacteriocins in enhancing food preservation in detail. The combination of bacterioncins and other hurdles provide potential approaches for maintaining food quality and food safety.

Invited review: Advances in nisin use for preservation of dairy products

Dairy product safety is a global public health issue that demands new approaches and technologies to control foodborne pathogenic microorganisms. Natural antimicrobial agents such as nisin can be added to control the growth of pathogens of concern in dairy foods, namely Listeria monocytogenes and Staphylococcus aureus. However, several factors affect the antimicrobial efficacy of nisin when directly added into the food matrix such as lack of stability at neutral pH, interaction with fat globules, casein, and divalent cations. To overcome these limitations, new and advanced strategies are discussed including nisin encapsulation technology, addition to active packaging, bioengineering, and combination with other antimicrobials. This review highlights advanced technologies with potential to expand and improve the use of nisin as a dairy preservative.

Diterpenoids and sesquiterpenoids from the stem bark of Metasequoia glyptostroboides

A phytochemical study on the stem bark of Metasequoia glyptostroboides led to the isolation of sixty-one diterpenoids and sesquiterpenoids, including seventeen previously undescribed compounds, metaglyptins A-Q. Their structures were elucidated by extensive analysis of spectroscopic data (IR, UV, HRESIMS, and ¹H, ¹³C and 2D NMR). The absolute configurations of metaglyptins I, J, and O were determined by the ECD data and single-crystal X-ray diffraction analysis. The undescribed compounds were evaluated for their cytotoxicity against HeLa, AGS, and MDA-MB-231 cancer cell lines. The results revealed that metaglyptin A exhibited moderate cytotoxicity against MDA-MB-231 cell line with IC₅₀ value of 20.02 μM.

ENSURING FOOD SECURITY THROUGH ENHANCING MICROBIOLOGICAL FOOD SAFETY

Food safety and food security are interrelated concepts with a profound impact on the quality of human life. Food security describes the overall availability of food at different levels from global to individual household. While, food safety focuses on handling, preparation and storage of foods in order to prevent foodborne illnesses. This review focuses on innovative thermal and non-thermal technologies in the area of food processing as the means to ensure food security through improving food safety with emphasis on the reduction and control of microbiological risks. The antimicrobial efficiency and mechanism of new technologies to extend the shelf life of food product were also discussed.

Growing with dinosaurs: natural products from the Cretaceous relict Metasequoia glyptostroboides Hu & Cheng-a molecular reservoir from the ancient world with potential in modern medicine

After the sensational rediscovery of living exemplars of the Cretaceous relict Metasequoia glyptostroboides-a tree previously known exclusively from fossils from various locations in the northern hemisphere, there has been an increasing interest in discovery of novel natural products from this unique plant source. This article includes the first complete compilation of natural products reported from M. glyptostroboides during the entire period in which the tree has been investigated (1954-2014) with main focus on the compounds specific to this plant source. Studies on the biological activity of pure compounds and extracts derived from M. glyptostroboides are reviewed for the first time. The unique potential of M. glyptostroboides as a source of bioactive constituents is founded on the fact that the tree seems to have survived unchanged since the Cretaceous era. Since then, its molecular defense system has resisted the attacks of millions of generations of pathogens. In line with this, some recent landmarks in Metasequoia paleobotany are covered. Initial spectral analysis of recently discovered intact 53 million year old wood and amber of Metasequoia strongly indicate that the tree has remained unchanged for millions of years at the molecular level.