(post-racking) and control of the spoilage yeast Brettanomyces. These products and uses are approved for European use by the EU and OIV standards. Wound management Chitosan based wound dressings have been widely explored for a variety of acute and chronic wounds. Chitosan has the ability to adhere to fibrinogen, which produces increased platelet adhesion, causing clotting of blood and hemostasis. Chitosan hemostatic agents are salts made from mixing chitosan with an organic acid (such as succinic or lactic acid). Chitosan may have other properties conducive to wound healing, including antibacterial and antifungal activity, which remain under preliminary research. Chitosan is used within some wound dressings to decrease bleeding. Upon contact with blood, the bandage becomes sticky, effectively sealing the laceration. Chitosan hydrogel-based wound dressings have also been found useful as burn dressings, and for the treatment of chronic diabetic wounds and hydrofluoric acid burns. Chitosan-containing wound dressings received approval for medical use in the United States in 2003. Temperature-sensitive hydrogels Chitosan is dissolved in dilute organic acid solutions but is insoluble in high concentrations of hydrogen ions at pH 6.5 and is precipitated as a gel-like compound. Chitosan is positively charged by amine groups, making it suitable for binding to negatively charged molecules. However, it has disadvantages such as low mechanical strength and low-temperature response rate; it must be combined with other gelling agents to improve its properties. Using glycerolphosphate salts (possessing a single anionic head) without chemical modification or cross-linking, the pH-dependent gelation properties can be converted to temperature-sensitive gelation properties. In the year 2000, Chenite was the first to design the temperature-sensitive chitosan hydrogels drug delivery system using chitosan and β-glycerol phosphate. This new system can remain in the liquid state at room temperature, while becoming gel with increasing temperature above the physiological temperature (37 °C). Phosphate salts cause a particular behaviour in chitosan solutions, thereby allowing these solutions to remain soluble in the physiological pH range (pH 7), and they will be gel only at body temperature. When the liquid solution of chitosan-glycerol phosphate, containing the drug, enters the body through a syringe injection, it becomes a water-insoluble gel at 37 °C. The entrapped drug particles between the hydrogel chains will be gradually released. Research Chitosan and derivatives have been explored in the development of nanomaterials, bioadhesives, wound dressing materials, improved drug delivery systems, enteric coatings, and in medical devices. Among chitosan derivatives in particular thiolated chitosans