A device containing a temperature-sensitive material comprises a first part containing the material, a second part which engages the first part and allows, or can be disengaged or displaced to allow, the material to be dispensed or utilised, a locking means, and a temperature-sensitive activator for the locking means that is activated at a predetermined temperature, and thereby irreversibly prevents the material from being dispensed or utilised should it become frozen or exposed to temperatures below a predetermined limit.