Is it safe to eat oysters in months with the letter R in them?

• Adam Liaw's oyster platter with homemade hot sauce

​What is the story about not eating oysters in months with the letter "r" in them. Fact or fiction? J. Cool

That thing about Rs and months is American. And it's true and has been for thousands of years. Indigenous Americans left great middens of oyster shells on the east coast of America. They were eating their oysters in their warmer months from May to August but not eating oysters from September to April in the colder months. During these chilly months a parasitic snail emerges to attacks oysters. So it made good sense to the indigenous Americans to leave the oysters alone when they were under attack. Here, in Australia, we don't have the same, seasonal parasitic snail. We can eat oysters all year round, with exceptions. Sydney rock oysters are generally at their peak from September to March. But nature can get in the way. High rainfall can wash undesirable nutrients into estuaries. When this happens the authorities close down the waterways to harvest until tests prove there is no threat to human health. Moon, tide and rainfall can cause oysters to spawn and, like the rest of us, after mating, they need some time to recover. Same goes for the Pacific oysters from South Australia and Tasmania. Except for the growers who stock triploids. These are Pacific oysters that have been bred to have no gender, do not spawn, and grow fat and juicy despite the conditions.

How is it possible to have a vegan butcher?

I find the field of fake meat fascinating. I made a point of meeting Jaap Korteweg, the Vegetarian Butcher in The Hague in The Netherlands. Lovely chap. He opened his butcher shop opposite the train station in 2010. Lined with tiles like an old-fashioned butcher shop, his beautiful store stocked meat analogues such as sausages, burgers and tuna. He made his products from vegetables and pulses and they tasted really good. Seriously. They were good. He sold his business to the mammoth multinational Unilever last year. Big business has it eyes on meat-free food. There was an application made to Food Safety Australia New Zealand last year by Impossible Foods Inc to sell products made with soy leghemoglobin produced by genetically modified yeast to make burgers taste bloody. If the application is passed you could be eating a GM vegan burger in a fast-food joint and, unless you ask, you could be none the wiser. But I digress. The word butcher comes to us from an old Anglo-Norman French variant of Old French bochier, a goat slaughterer from boc, a "he-goat", or buck. That said, you'd have to be pretty thick to think a vegan butcher is going to sell meat.

Letters

We talked recently about the risk of contracting parasites from eating raw kangaroo. One reader, Jim, wrote, "Not sure about Australia but in NZ all farm-killed meat must be frozen before it is consumed by either people, dogs or pigs. The idea is to kill any parasites. The meat is only safe if frozen to -10 degrees for 20 days." Interesting.

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