While perhaps not the most appetising option, if your food strainer has gone missing and you need an alternative according to Instructables user Carleyy you can use pantyhose:
To prevent food from getting down your sinks drain cover your bowl with a pair of pantyhose before pouring it in the sink. This is useful when you are having soup and you don't want to throw away the liquid in the trash.
While you could technically use this method for food you're actually going to eat, such as straining the water from pasta, that's probably not the best option. But when you're without a garbage disposal and don't want to pick food out of the sink later this can get the job done.
Pantyhose: Food Strainer [Instructables]