Patent For Anti-Listerial Mixed Culture For Making Cheese Awarded To CSK
Washington—The US Patent and Trademark Office (USPTO) recently awarded a patent for an invention related to a method of recombinantly producing a nonbovine chymosin.
Inventors are Stefan Kappeler, Zakaria Farah, Johannes Maarten Van den Brink, Henrik Rahbek- Nielsen and Peter Budtz. The patent was assigned to Chr. Hansen A/S, Horsholm, Denmark, and Eidgenossische Technische Hochschule, Zurich, Switzerland.
For the purposes of this invention, the phrase “non-bovine” refers to any non-Bos taurus mammalian species where pre-prochymosin is produced naturally in the gastrointestinal tract. Such species include ovine species, caprine species, Camelidae species comprising the genus Camelus with the two species Camelus dromedarius and Camelus bactrianus, buffalo species including water buffaloes, the genus Lama, and the genus Vicugna.
Whereas chymosin is produced naturally in mammalian species including ruminant speces, bovine chymosin and (to a lesser extent) caprine chymosin are currently the only of these animal chymosin species that are commercially available to the dairy industry, according to the patent’s background. Bovine chymosin, in particular calf chymosin, is commercially available both as stomach enzyme extracts (rennets) comprising the natively produced chymosin and as recombinantly produced chymosin which is expressed in bacterial, yeast or fungal host cells.
Recently, studies on functional characteristics of rennet extracted from the stomach of Camelus dromedarius chymosin have been reported, and it has been found that the clotting time of camel’s milk is significantly reduced when camel rennet is used instead of bovine calf rennet, the patent background explained. It is evident, therefore, that more effective clotting of camel’s milk could be achieved at an industrial level were camel chymosin commercially available, and it is also conceivable that camel chymosin is highly suitable as a cow’s milk clotting enzyme as well.
The inventors have found that it is possible to provide industrially highly useful non-bovine chymosin using recombinant DNA technology at a production yield level which, relative to that which can be obtained in current, optimized bovine chymosin production systems, is significantly improved, the background noted.
The invention has made it possible to provide, for the first time, camel chymosin in sufficient quantities to render an industrial, cost-effective and high quality production of cheese based on camel’s milk possible, which, due to the scarcity of camel calf stomach material, has not hitherto been possible, the background stated.
CSK Patent The USPTO has also awarded a patent for an invention that discloses a method for producing a fermented dairy product comprising inoculating milk with lactic acid bacteria capable of producing a Class IIa type bacteriocin; and lactic acid bacteria capable of producing a Class I type bacteriocin.
Inventors are Carmel Griffin, Susan Mills, Paul Ross, Willem Cornelis Meijer, and Mourdes Mariela Serrano Davalos. The patent was assigned to CSK Food Enrichment.
In a first aspect the invention provides a method for producing a fermented product, in particular a cheese, said method comprising inoculating milk with: one or more strains of lactic acid bacteria capable of producing a Class IIa type bacteriocin; and one or more strains of lactic acid bacteria capable of producing a Class I type bacteriocin; and, optionally, one or more further lactic acid bacterial strains.
It was found that the combination of the one or more strains of lactic acid bacteria, one capable of producing a Class IIa type and the other a Class I type bacteriocin, respectively, yielded a significantly enhanced kill-off of viable Listeria in fermented dairy products as compared with the anti-listerial effect achievable by inoculating the milk with said individual strains at comparable rates.
It also provides a mixed lactic acid bacterial culture composition comprising: one or more strains of lactic acid bacteria capable of producing a Class IIa bacteriocin; and one or more strains of lactic acid bacteria capable of producing a Class I type bacteriocin; and optionally, one or more further lactic acid bacterial strains.
