Sterilising the bottle

Hi. My mum is using the Neil Med sinus rinse daily on recommendation of an ENT specialist.  He told her to sterilise the bottle every day before use in the microwave. We are planning to go on holiday and my mum is concerned that she will need to take a week's worth of bottles as she won't have access to a microwave. However, she spoke to someone at Neilmed who said you shouldn't sterilise the bottle every day in any case as it degrades the plastic. Please could we have some advice?