假设这样一种情况：如果明天起，人类突然全部消失不见，那么等到两千年后，当那时的考古学家来到你我的厨房考察，寻找当年保存的食物时，还有哪些能吃？人类有各种各样新奇的食物保存方法。比如，将食物冷冻干燥、用食盐腌渍、放入真空包装密封起来。本期 “随身英语” 节目介绍哪些食物保存法最有效，以及有什么方法可以让食物保存2000年后依然可以食用。

词汇：food preservation 食品保存

Imagine for a moment you've travelled 2,000 years into the future. Which human foods do you think would stand the test of time, and would any of it still be edible? To find out, we first need to understand what makes food go off.

Food preservation's main opponent is microbial growth. An expert in food chemistry, Michael Sulu, says most foods spoil for that reason. When things like bacteria, mould and yeast grow on your food, it can become pathogenic, and food causing disease is best avoided! So, how can we limit their growth?

Microbes love oxygen and water, so the key is to starve them of it. We can do this by drying, salting, chilling, or storing the food in airtight containers. According to Sulu, drying is the most effective because without water, microbes can't multiply. Freezing works in the short-term, but explorers who have found ancient frozen animals initially thought the meat looked edible, but once defrosted, it immediately became putrid, which doesn't sound at all palatable!

But how can we make our favourite foods longer-lasting if we don't want to dry, salt or freeze them? That's where additives and preservatives come in. These chemicals help to improve the shelf life of our supermarket items, but it means the food becomes ultra-processed. High consumption of ultra-processed food is linked to problems like depression and obesity, according to a review of the research by Pagliai and colleagues in the British Journal of Nutrition.

So, what's going to be safe for us to eat in our hypothetical time travel scenario? "I would start off with anything that is vacuum-packed or dried as well," says Sulu. If you can't find any of that, you could go to the Global Seed Vault in Svalbard, Norway, where there are almost one million samples of seeds from all over the world. They're in vaults designed to last forever, buried beneath the Arctic permafrost, so either eat the seeds, or start repopulating the plant world!

词汇表

stand the test of time 经得起时间的考验
edible 可食用的
go off （食物）变坏
food preservation 食品保存
microbial growth 微生物生长
spoil （食物）变坏，变质
bacteria 细菌
mould 霉菌
yeast 酵母菌
pathogenic 可致病的
salting 用食盐腌制
airtight 密封的
defrost 解冻
putrid 腐烂的，腐坏的
palatable 美味的，可口的
long-lasting 持久的，长期的
additives 添加剂
preservatives 防腐剂
shelf life 保质期
ultra-processed 超加工的
vacuum-packed 真空包装的
permafrost 永冻层，永久冻土

测验与练习

1. 阅读课文并回答问题。

1. What is the main reason our food spoils?

2. Why is drying considered the most effective food preservation method?

3. True or False? Frozen meat is edible even 2,000 years in the future.

4. What is the downside of adding additives and preservatives to food?

5. How are the seeds in the Global Seed Vault stored?

2. 选择意思恰当的单词或词组来完成下列句子。

1. Salt is often used in _______ methods to inhibit microbial growth.

vacuum-packed food preservation pathogenic edible

2. If milk starts to smell sour, it's a sign that it _______.

has gone off stands the test of time goes off stood the test of time

3. Leaving food in the sun can cause it to _______ quickly.

ultra-process spoil defrosting preserve

4. The chef experimented with different spices to make the dish more _______.

airtight pathogenic long-lasting palatable

5. That bread is quite old. Look, it's already got _______ on it!

frost additives salt mould

答案

1. 阅读课文并回答问题。

1. What is the main reason our food spoils?

The main reason our food spoils is microbial (bacteria, mould, yeast) growth.

2. Why is drying considered the most effective food preservation method?

Drying is considered the most effective food preservation method because microbes can’t multiply without water.

3. True or False? Frozen meat is edible even 2,000 years in the future.

False. Explorers found meat they thought was edible, but once it was defrosted, it became putrid.

4. What is the downside of adding additives and preservatives to food?

Adding additives and preservatives to food makes them more likely to be ultra-processed, the consumption of which is linked to depression and obesity.

5. How are the seeds in the Global Seed Vault stored?

The seeds in the Global Seed Vault are stored in vaults designed to last forever, buried beneath the Arctic permafrost.

2. 选择意思恰当的单词或词组来完成下列句子。

1. Salt is often used in food preservation methods to inhibit microbial growth.

2. If milk starts to smell sour, it's a sign that it has gone off.

3. Leaving food in the sun can cause it to spoil quickly.

4. The chef experimented with different spices to make the dish more palatable.

5. That bread is quite old. Look, it's already got mould on it!