Food preservation - Seven Wonders of the Microbe World (3/7)
Summary
TLDRMicrobes 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
🍽️ 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.
Mindmap
Keywords
💡Microbes
💡Food preservation
💡Gastroenteritis
💡Salting
💡Boiling
💡Canning
💡Pickling
💡Refrigeration
💡Yeast
💡Fermentation
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….
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