A microtiter plate-based enzyme immunoassay has been developed for phaseolinone, a phytotoxin isolated from the culture filtrate of the plant-pathogenic fungus Macrophomina phaseolina (Tassi) Goid. The smallest amount of phaseolinone detectable by the method is 5 pg per well. The method is validated by comparison with high-performance liquid chromatography and used to confirm and estimate phaseolinone production in seeds infected with the fungus. The degree of seed inhibition correlated well with the amount of toxin produced in infected seeds, 50% inhibition being observed at a toxin concentration of 0.60 micrograms/g of wet tissue.
Meat and meat products are perishable in nature, and easily susceptible to microbial contamination and chemical deterioration. This not only results in an increased risk to health of consumers, but also causes economic loss to the meat industry. Some microorganisms of the lactic acid bacteria (LAB) group and their ribosomal-synthesized antimicrobial peptides—especially bacteriocins—can be used as a natural preservative, and an alternative to chemical preservatives in meat industry. Purified or partially purified bacteriocins can be used as a food additive or incorporated in active packaging, while bacteriocin-producing cells could be added as starter or protective cultures for fermented meats. Large-scale applications of bacteriocins are limited, however, mainly due to the narrow antimicrobial spectrum and varying stability in different food matrixes. To overcome these limitations, bioengineering and biotechnological techniques are being employed to combine two or more classes of bacteriocins and develop novel bacteriocins with high efficacy. These approaches, in combination with hurdle concepts (active packaging), provide adequate safety by reducing the pathogenicity of spoilage microorganisms, improving sensory characteristics (e.g., desirable flavor, texture, aroma) and enhancing the shelf life of meat-based products. In this review, the biosynthesis of different classes of LAB bacteriocins, their mechanism of action and their role in the preservation of meats and meat products are reviewed.
The production of phaseolinone, a phytotoxic metabolite of Macrophomina phaseolina in infected Phaseolus mungo seeds grown on soil, was estimated by enzyme‐linked immunosorbent assay and HPLC. The degree of inhibition of seed germination correlated well with the amount of toxin produced; 50% inhibition was observed at a toxin level of 2.1 μg g‐1 of wet tissue. A comparison of the toxin‐producing ability of nine isolates of the fungus obtained from different hosts and localities showed that the strain MPK'83 produced a significantly larger amount of the toxin, both in liquid culture and in infected seeds. The virulence of the isolates was related to their ability to produce phaseolinone.
The meat industry requires prompt and effective control measures to guarantee the quality and safety of its products and to avert the incidence of foodborne illnesses and disease outbreaks. Although standard microbiological methods and conventional analytical techniques are employed to monitor the quality and safety, these procedures are tedious and time-consuming, require skilled technicians, and sophisticated instruments. Therefore, there is an urgent need to develop simple, fast, and user-friendly hand-held devices for real-time monitoring of the quality of meat and meat products in the supply chain. Biosensors and chemical indicators, due to their high sensitivity, specificity, reproducibility, and stability, are emerging as promising tools and have the potential for monitoring and controlling the quality (freshness and sensory traits such as tenderness) and safety (metabolites, contaminants, pathogens, drug residues, etc.) of muscle foods. In this review, the application of biosensors in the meat industry and their emerging role in the quantification of key meat quality components are discussed. Furthermore, the role of different biosensors to identify and detect contaminants, adulterants, pathogens, antibiotics, and drug residues in meat and meat products is also summarized.
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