On Wednesdays, Kate usually buys some guava juice  But the only place she can buy guava juice is the local health food store
It follows that she must sometimes shop at the local health food store on Wednesdays
Only teachers at the Culinary Institute are allowed to use the institute's main kitchen. Most dinners at Cafe Delice are prepared in that kitchen. So at least some dinners at Cafe Delice must be prepared by Culinary Institute teachers.