As the oldest child of my older sister, she’s more qualified than most to talk about Best By Dates – because my older sister has an obsession about following instructions, including those on packaging and in cookbooks. Not for her the instinctive Italianate-style cooking that makes for wonderful TV viewing: the happy oil-sloshing, the carefree garnish-sprinkling, the tasting and smiling and adding of a little – poco! – more seasoning.

No, my sister’s idea of running a kitchen is more like that of a strict 70-year-old naval officer with control issues. Measuring spoons essential. Liquids poured to within .001 of the required quantity. And if anything in the refrigerator is one day past its expiry date, believe me, heads will roll.

‘Do you remember Mum’s obsession with Best By Dates?’ asks my niece in an uncanny act of mind-reading. ‘Do I!’ I exclaim. I tell her how, as a teenager, I imagined the dairy products cowering in the fridge as they approached the last hour of their shelf life and my sister was near. ‘She went to bed at 11 on the dot, every night of her teenage life, so at 10.45 she would march into the kitchen and raid the fridge. Any food whose expiry date was that day would be swept into the bin.’

‘But food doesn’t go off from one minute to the next, does it?’

‘According to her, as soon as midnight came, the food would instantly became inedible.’ I laugh, remembering my mother’s despairing face when she’d come downstairs for her morning bowl of muesli, yoghurt and milk – and find only the muesli had survived the purge.

Walking to my own fridge, I open it rather dubiously. Although I find my sister’s behaviour bizarre, sometimes I wish that my partner and I had a slightly less relaxed attitude to the expiry-date issue. If only, I think, our bulging Bosch fridge was like that in the kitchen of a restaurant – swiftly filled and swiftly emptied, instead of being filled, and filled, and filled… until the smell knocks you flat on your back!

I sniff and gingerly investigate the back shelves. My partner has a habit of sticking anything that’s becoming slightly stinky in opaque plastic bags and then forgetting them, so many months later one has dozens of unmarked white-plastic mould bombs to deal with.

Today it’s not so bad, mainly because both we’ve both been away most of the summer and have had little time to stockpile groceries. ‘Hungry?’ I say to my niece, extracting pulling only slightly wilted greens, only slightly curling salami and only slightly murky bottled capers.

She wrinkles up her delicate teenage nose. ‘Blue cheese – yuck! Do you really like that stuff?’

‘I really love it,’ I say fervently, peeling off the damp clingfilm and smearing a layer on a cracker. ‘It’s dairy-divineness!’ But I don’t tell her the real reason I love blue cheese: for its guilt-free, danger-free qualities. Because mouldiness is a prerequisite part of its charms, it’s much less likely that it’ll be confiscated from your fridge and you’ll receive an order from Captain Best-By to walk the plank.