Food preservation - Seven Wonders of the Microbe World (3/7)

Summary

Microbes play a dual role in food, aiding in the production of delights like cheese and beer, while also causing gastroenteritis through contamination. Ancient preservation methods like salting, drying, and fermentation are still used today to combat harmful microbes. Temperature manipulation, such as refrigeration and boiling, helps preserve food by inhibiting microbial growth. Canning, developed by Nicholas Appert, further extends shelf life. Alcohol and acidic environments like vinegar also deter microbes, ensuring food safety and quality.

Takeaways

• 🍽️ Microbes play a dual role in food, being essential for creating products like cheese, bread, yogurt, and beer, but also causing harm when they lead to foodborne illnesses like gastroenteritis.
• 🏥 In the UK, there are over ten million cases of gastroenteritis annually, often resulting from consuming food contaminated with harmful microbes.
• 🛡️ Ancient preservation methods like salting, drying, icing, pickling, smoking, and fermentation are still used today to prevent microbial growth and food spoilage.
• 💧 Microbes require water to grow, and by making food very sugary or salty, we can deny them this essential resource, thus preserving the food.
• 🌡️ Temperature manipulation is a key preservation strategy; refrigeration slows microbial growth, while boiling can kill most microbes, though some resistant bacteria require higher temperatures to be eradicated.
• 🔬 The French confectioner Nicholas Appert developed canning in the 1790s, a method that involves heating food in sealed containers to eliminate microbes through high temperatures.
• 🍶 Alcohol and acidic environments like vinegar are inhospitable to many microbes, making them effective for food preservation, as seen in the production of Branston pickle.
• 🧊 Refrigeration only slows down microbial growth, it does not kill all microbes, which means that food can still spoil if left for extended periods.
• 🔍 The script underscores the importance of understanding microbial behavior in food to ensure safety and extend shelf life, highlighting both the benefits and risks associated with different preservation techniques.
• 📚 The historical context provided by the script shows how human ingenuity in food preservation has evolved over time, from ancient methods to modern-day applications.

Q & A

What role do microbes play in food production?

Microbes are responsible for creating some of our most enjoyable food products such as cheese, bread, yogurt, and beer.

Which harmful microbes are mentioned in the script that can cause gastroenteritis?

The harmful microbes mentioned are Salmonella, Listeria, and E.coli O157.

What is the impact of consuming contaminated food on human health?

Consuming contaminated food can lead to gastroenteritis, which includes symptoms like nausea, vomiting, diarrhea, and stomach pain.

How many cases of gastroenteritis are reported annually in the UK according to the script?

In the UK alone, there are more than ten million cases of gastroenteritis each year.

What is one of the first things that happens to fresh food when left lying around?

If you leave fresh food lying around, microbes land on it and start to deteriorate the food.

What is one way ancient people discovered to stop food from spoiling?

Ancient people discovered that one way to stop food from spoiling is to try and preserve food.

List some methods of food preservation mentioned in the script.

Methods of food preservation mentioned are salting, drying, icing, pickling, smoking, and fermentation.

How can microbes be denied water to prevent their growth?

Microbes can be denied water by turning the food very sugary, for example making jam, or by putting salt on our food.

What is the effect of temperature on the growth of microbes?

Many microbes are sensitive to temperature and don't like cold or hot temperatures, so changing the temperature can help preserve food.

What is the common method of food preservation using high temperature under pressure?

Canning is a common method of food preservation using high temperature under pressure.

Who developed the canning method and what did he preserve using this technique?

The canning method was developed by the French confectioner Nicholas Appert. He preserved soups, vegetables, juices, dairy products, jellies, jams, and syrups.

How do alcohol and acid help in preserving food?

Many microbes can't survive in alcohol or acid conditions such as vinegar or pickling, making them effective forms of preservation.

What is the effect of refrigeration on microbes on food?

Refrigerating food slows down the growth of microbes but does not actually kill them.

Outlines

00:00

🍽️ Microbes in Food: Friend and Foe

This paragraph discusses the dual role of microbes in food production. On one hand, they are essential for creating popular food items like cheese, bread, yogurt, and beer. On the other hand, harmful microbes such as Salmonella, Listeria, and E.coli O157 can cause severe health issues like gastroenteritis, with over ten million cases reported annually in the UK alone. The symptoms include nausea, vomiting, diarrhea, and stomach pain, typically resulting from consuming contaminated food. The ancient practice of food preservation, which includes methods like salting, drying, icing, pickling, smoking, and fermentation, is highlighted as a way to prevent microbial growth and toxin production. The sensitivity of microbes to temperature is also mentioned, with refrigeration and boiling being common preservation techniques. The paragraph concludes with a mention of high-pressure canning, pioneered by Nicholas Appert in the 1790s, and the use of alcohol and acid as preservation methods.

Keywords

💡Microbes

Microbes are tiny organisms, including bacteria, viruses, and fungi, that are responsible for various effects on food. They can either contribute to food production, like in the case of cheese and beer, or cause harm, leading to illnesses such as gastroenteritis. In the context of the video, microbes are central to both the creation of enjoyable foods and the contamination that leads to food poisoning.

💡Food preservation

Food preservation refers to methods used to prevent food from spoiling and to keep it safe to eat over time. In the video, various traditional techniques like salting, drying, pickling, and fermentation are highlighted as ways to prevent microbial growth. These techniques block or slow down the activity of harmful microbes that can spoil food or produce toxins.

💡Gastroenteritis

Gastroenteritis is an illness characterized by nausea, vomiting, diarrhea, and stomach pain, typically caused by consuming contaminated food. The video mentions how over ten million cases occur in the UK each year due to foodborne microbes like Salmonella and E.coli. This condition illustrates the dangers posed by harmful microbes when food is not properly preserved or handled.

💡Salting

Salting is a method of food preservation in which salt is applied to food to inhibit microbial growth. Salt draws moisture out of the food, creating an environment where most microbes cannot survive. The video explains that this technique was used to preserve meat before the invention of refrigerators, effectively blocking microbial contamination.

💡Boiling

Boiling is a common food preservation technique that involves heating food to high temperatures to kill microbes. While boiling kills most microbes, some bacteria are resistant and require even higher temperatures to eliminate. The video highlights boiling as a way to preserve food by destroying microbes, though it cautions that not all bacteria can be killed by this method alone.

💡Canning

Canning is a method of food preservation where food is sealed in containers and then heated to kill microbes. This technique was pioneered by Nicholas Appert in the 1790s. By heating food under pressure, canning can achieve higher temperatures than boiling, killing even heat-resistant microbes. The video uses this example to explain how modern preservation techniques were developed to keep food safe for longer periods.

💡Pickling

Pickling involves preserving food in an acidic environment, such as vinegar, which creates inhospitable conditions for microbial growth. In the video, pickling is mentioned as a method responsible for the creation of iconic products like Branston pickle, which has been using this preservation technique since 1922. The acid prevents harmful microbes from thriving.

💡Refrigeration

Refrigeration is the process of cooling food to slow down the growth of microbes. The video explains that while refrigeration doesn't kill microbes, it inhibits their activity, preserving food for longer. However, when food is left for extended periods, such as after a holiday, microbial growth can still occur even in the fridge, leading to spoilage.

💡Yeast

Yeast is a type of microbe that thrives in alcoholic environments and plays a key role in fermentation, a process used to make products like beer and bread. In the video, yeast is mentioned as an exception among microbes because it can survive in alcohol, making it useful for food preservation and production. Yeast’s ability to withstand alcohol contrasts with the vulnerability of other microbes in such conditions.

💡Fermentation

Fermentation is a biochemical process in which microbes like yeast and bacteria convert sugars into acids, gases, or alcohol. This process is used to create foods like cheese, beer, and bread, which are mentioned in the video. Fermentation not only produces desirable flavors and textures but also acts as a preservation method by making food environments unsuitable for harmful microbes.

Highlights

Microbes play a dual role in food production, being essential for some products like cheese and bread, while harmful ones like Salmonella can cause illness.

In the UK, there are over ten million cases of gastroenteritis annually due to food contaminated by microbes.

Ancient methods of food preservation, such as salting and fermentation, are still in use today to prevent microbial growth.

Microbes are sensitive to temperature, which can be exploited for food preservation through refrigeration or boiling.

Boiling food is a common preservation method that kills most microbes but not all, as some bacteria are resistant to 100 degrees Celsius.

To eliminate all bacteria, a temperature of 121 degrees Celsius is required, achievable by pressurized heating, a technique used in canning.

Canning, developed by Nicholas Appert in the 1790s, involves placing food in glass jars, sealing, and boiling to preserve it.

Alcohol and acid, such as vinegar, create inhospitable environments for microbes, making them effective preservation methods.

The production of Branston pickle in 1922 demonstrates the long-standing use of pickling to preserve food and prevent microbial growth.

Refrigeration slows down microbial growth but does not kill microbes, which means food can still spoil if left for extended periods.

Microbial sensitivity to temperature can be used to preserve food by changing its temperature, such as through refrigeration or boiling.

Salting food, a traditional method, denies microbes water and prevents their growth, which was particularly useful before the invention of refrigerators.

Making jam or using sugary substances to preserve food is another way to deny microbes the moisture they need to thrive.

Nicholas Appert's experiments with canning led to the preservation of a wide range of foodstuffs, from soups to dairy products.

The use of alcohol for food preservation leverages the fact that many microbes cannot survive in alcoholic environments.

The production of Branston pickle has been successful for nearly a century, demonstrating the effectiveness of pickling as a preservation method.

The transcript emphasizes that refrigeration is not a permanent solution for food preservation, as it only slows microbial growth.

Transcripts

Microbes are responsible for creating some of our most enjoyable food products such as

cheese, bread, yogurt and of course beer.

But other microbes, such as Salmonella, Listeria,

E.coli O157 can do us a great deal of harm.

In the UK alone, there are more than ten million cases of gastroenteritis each year – a

concoction of symptoms such as nausea, vomiting, diarrhea and stomach pain, caused by

eating and drinking food contaminated by microbes. Since ancient times we have done our

utmost to keep them out.

If you leave fresh food lying around one of the first things that happens is that microbes

land on it and this starts to deteriorate the food

over time. And one of the worst things they can do

is start to produce toxins that can be poisonous to anyone eating that food. And the ancients

discovered a very, very long time ago that one way to stop this is to try and preserve

food.

They used a variety of methods – such as salting, drying, icing, pickling, smoking

and fermentation for beer, cheese and bread – all

of which we still use today.

You can deny microbes water by turning the food very sugary, for example making jam – or

we can put salt on our food, and that’s why people used to salt meat in the days before

refrigerators, to stop microbes from growing. One of the characteristics of microbes is

that they’re very sensitive to temperature. Many of

them don’t like cold temperatures – many of them don’t like hot temperatures and

so we can preserve food by changing its temperature.

One way in which we do this is to put food in a

refrigerator. We also boil food – that’s a very common

way to preserve it and the way in which that’s working is to kill microbes that can’t really

grow at high temperatures.

Boiling doesn’t kill all the microbes, just most of them. Some bacteria are actually resistant

to the temperature of boiling water, which is

100 degrees celsius. To get rid of them all you need

to raise the temperature to about 121 degrees – but you can only do this heating water

under pressure.

A common method of food preservation using this technique, is canning, which was

developed by the French confectioner, Nicholas Appert, In the 1790s, Appert began

experimenting with ways to preserve foodstuffs, succeeding with soups, vegetables, juices,

dairy products, jellies, jams, and syrups. He placed the food in glass jars, sealed them

with cork and sealing wax and placed them in boiling

water. And then there’s alcohol and acid …

Tom Many microbes can’t survive in alcohol;

yeast can which makes it an effective form of

preservation. Acid conditions, such as vinegar, or pickling, are also inhospitable environments

for microbes.

Pickling to block microbes is responsible for some of our most famous brands. In 1922,

in Burton, Staffs, Cross and Blackwell produced

the very first jar of Branston pickle. 28 million

jars of it are now sold every year – still keeping out the microbes as it did 90 years

ago.

One thing you have to remember is that if you refrigerate food and the microbes on it

– you only slow down the growth of the microbes

– you don’t actually kill them.

So when you get back from holiday, all might not quite be as you left it….