What to do with Mouldy Food? Use or Discard? 发霉的食物怎样处理？吃还是不吃？

广东疾控 · 公众号 · 养生 · 2017-03-21 21:43

正文

Moulds

霉菌

Talking about moulds, their disgusting appearances such as grey patches, fuzzy green dots and white dust may instantly come up to your mind. You will probably get mad when they do their best trick to spoil your favourite food. You may also have heard of moulds forming dangerous toxins. In this article, let’s take off our tinted glasses and have a closer look on these microorganisms to see if they are really heinous.

一说到霉菌，大家的脑海里可能会马上浮现出那些灰蒙蒙的霉斑、绿碜碜的霉点和白毛。眼看着心爱的美食被这些东西蚕食已经令人气愤，更何况听说霉菌还会产生有害的毒素。这些微生物是否十恶不赦？大家姑且先放下有色眼镜，看完本文后自有分晓。

What are Moulds？

Moulds are fungi that can be found virtually in every environment. They are common in Hong Kong because our warm and humid climate is conducive to their growth; however, they can also grow at refrigerating temperatures. These microorganisms grow well on most types of food and if you notice their presence in food, it is generally a sign of spoilage.

Moulds reproduce by tiny spores which are invisible to the naked eyes and spread through air, water or other means including food handling. After landing in a suitable environment such as food, spores can germinate and grow. When the mould colony is large enough, you may see them with naked eyes. However, sometimes you may not be aware that moulds are present in your food, particularly if their colour has low contrast against that of the surrounding product. For instance, grey patches are readily visible on white bread but difficult to be seen on dark chocolate cake. Therefore, we may occasionally consume mould contaminated food which appears to be mould-free!

霉菌是什么？

霉菌属于真菌类，在周围的环境中无处不在。霉菌在香港很常见，因为本地气候温暖而潮湿，适宜霉菌的生长。不过，霉菌其实在冷藏的温度下也可以生长。大部分食物都是这些微生物的温床，当你一旦发现食物里长有霉菌，通常已是变质的征兆。

霉菌的繁殖方式是通过肉眼看不见的微小孢子，以空气、水或食物处理等其他方式散播。当遇到合适的地方，例如食物，孢子便萌发生长。当菌落够大时，我们肉眼也可以发现。不过，有时我们未必会留意到食物已经发霉，尤其是当霉菌的颜色与食物的颜色相似时。比如说，白面包上有灰斑当然一目了然，但如果灰斑长在黑巧克力蛋糕上说不定就逃过我们的眼睛了。所以，我们可能有时吃了受霉菌污染的食物而不自知。

Are Moulds Always Dangerous?

Most moulds are harmless and some are even desirable; in general acute toxicity resulted from the consumption of mouldy food is unlikely. Nevertheless, certain moulds can be dangerous. Some moulds can cause infection especially in patients with weakened immunity, such as patients infected with human immunodeficiency virus (HIV) or suffering from some chronic diseases (e.g. cancer), and some others can produce poisonous mycotoxins (toxins from fungi). Mycotoxins can cause acute and/or chronic health effects in humans, for example aflatoxins can cause acute liver damage and are best known for their potential in causing liver cancer.

霉菌都是危险的吗？

大部分霉菌都是无害的，有些甚至是有用的，一般因吃下发霉食物而引致急性中毒的机会不大。不过，某些霉菌是有危险的。有些霉菌可造成感染，对免疫力弱的人士，例如爱滋病患者或长期病(例如癌症)患者尤其危险；有些霉菌则可产生霉菌毒素(由真菌产生的毒素)。霉菌毒素可对人体造成急性和／或长期的健康影响，例如黄曲霉毒素可引致急性肝脏受损，最广为人知的是有可能引致肝癌。

Can Moulds be Desirable?

Some moulds are desirable. They can be used to give certain types of cheeses unique flavours and textures. For instance, the blue colour of blue veined cheeses such as Roquefort comes from a type of mould called Penicillium roqueforti added during the manufacturing process while other cheeses like Brie and Camembert contain white surface moulds. The moulds used to produce these cheeses are generally safe to eat.

In addition, some salamis, Italian salami for example, have a characteristic thin, white mould coating which is also edible.

霉菌也有益处？

有些霉菌是有益的，一些芝士独特的味道和质感便是拜霉菌所赐。例如罗克福芝士(Roquefort)等蓝纹芝士在制作过程中加入了罗克福尔青霉菌(Penicillium roqueforti)，令芝士呈蓝色纹理；而布里芝士 (Brie) 和卡门贝尔芝士(Camembert)的白色面层其实也是一种霉菌。这些用来制造芝士的霉菌一般可以安全食用。

此外，一些沙乐美肠，如意大利沙乐美肠表面一层特有薄薄的白色霉菌也是可以食用的。

What to do with Mouldy Food?

Use or Discard?

Even moulds are not always hazardous; they generally spoil food and affect the overall quality of the product. However, the major concern of mouldy food is still on whether the moulds have mycotoxin-producing ability. In general, mycotoxin producing moulds are primarily found in grain and nut crops, but are also known to be on celery, grape juice, apples and other produce. Inspection by the naked eyes is unable to tell if the mould present in food is harmful or not.

To ensure food safety, apart from food containing moulds as part of the manufacturing process, you should discard food when you see mould on it. Simply removing visible mould from food surface cannot guarantee food safety because root of the mould may have already been invaded deeply into the food (see diagram). For some dangerous moulds, poisonous substances are often contained in and around the roots and in some cases, toxins may even have spread throughout the food. In addition, spoiled food may also have bacteria growing along with the mould.

发霉的食物怎样处理？

吃还是不吃？

虽然霉菌并非全部都是有害的，但霉菌一般会令食物变质和影响食物整体的品质。然而，发霉食物最令人关注的还是关霉菌会否产生霉菌毒素。一般来说，产生霉菌毒素的霉菌主要存在于谷物和坚果类农作物，但芹菜、葡萄汁、苹果和其他产品都有可能含有霉菌毒素。单凭肉眼很难知道食物中的霉菌是否有害。

为确保食物安全，除了那些在制造过程中刻意加入的霉菌外，如发现食物有霉菌便应丢弃。单靠去除食物表面上肉眼可见的霉菌并不足以保证食物安全，因为菌丝可能已侵入食物深层(见图)。若干危险霉菌的有毒物质通常藏于菌丝内外，有时毒素甚至可能已蔓延到整个食物。此外，变质的食物除了霉菌外，通常也有细菌一起生长。

Root of the mould invades deeply into food. Simply removing visible mould from food surface cannot guarantee food safety.

To avoid food wastage, buy small amounts of food and use them as soon as possible can prevent food from turning mouldy. It is also important to keep food covered to prevent exposure to mould spores in the air and possible cross contamination. Perishable foods and leftovers should be refrigerated and consumed as soon as possible. For other foods, they should be stored in accordance with the storage instructions provided. If storage instructions are not available, store them in a cool and dry place before consumption.

菌丝可侵入食物深层，单靠去除食物表面上肉眼可见的霉菌并不足以保证食物安全。

为免浪费食物，我们应每次只买少量食物并尽快用完，以防食物发霉。此外，食物要盖好，以防接触到空气中的霉菌孢子，造成交叉污染。容易腐坏的食物和剩余的食物应放在雪柜并尽快食用。其他食物则应按照存放指示贮存，如没有指示，则应在食用前放在阴凉干燥的地方。

（来源：香港食物安全中心）

统筹：宁可儿

美编：雷未明

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