What are bacteria and how do they affect our food?

July 22, 2021 0 Comments

What are bacteria?

Before we can understand how bacteria affect your food, we need to define the term: what are bacteria?

How do we define bacteria?

Bacteria are single-celled microorganisms that can exist as independent organisms (free-living) or as parasites (dependent on another organism for life). They are approximately 0.5 to 2 microns in size. A grain of sand is 2 millimeters in size. This means that it could fit 1000 bacterial cells in a single grain of sand. This means that we can only see the bacterial cells through the microscope.

Aside from the microscope, bacteria form what we call “colonies” that have millions of cells that allow us to easily see the bacteria in a laboratory-grown medium known as agar plates. This is the simplest method used to identify and see bacteria. We use this method to count how many bacteria are present, for example, on a swab on a cutting board. More than 300 colonies are considered dirty and contaminated.

These were one of the first organisms that existed on our planet, so they are very, very old and have coexisted with humans since the beginning. There are millions of different types of bacteria, some good for you and some very dangerous for your health.

Where can you find bacteria?

Bacteria live in water, soil, plants, and animals. Bacteria are so prominent on earth that they also live in some of the most extreme environments, such as the deep ocean, hot springs, and there is even evidence that bacteria lived on Mars.

For example, human-level bacteria grow in your gut, on your skin, and on your hair (including your eyelashes). So much so, that recent research has shown that the composition of the different types of bacteria in your gut and skin is MORE only a fingerprint.

Bacteria also grow and survive in the food we eat, raw meat and vegetables by design must be cooked so that we as humans can consume these foods without getting sick from the bacteria that thrive in these environments.

There are two main distinctions for bacteria that we define as gram-positive and gram-negative bacteria.

We use this distinction to group the different types of bacteria based on their appearance and behavior. All commonly occurring bacteria fall into these two categories. Suffice it to say that we identify bacteria in the laboratory with a simple test that we use as a broad category to determine which bacteria we are observing. This test is known as a Gram stain. This means that there are two main types of bacteria that look and behave differently from each other. With this method we can see bacteria under the microscope.

This test also helps us see the shape of the bacteria. There are three forms, bacilli (rod-shaped), cocci (circular), and spirilla (corkscrew-shaped).

What do bacteria need to survive?

There are 6 elements in the environment that allow bacteria to grow and survive:

Temperature

Moisture content

pH

Nutritive content

Oxygen

Hour

Temperature

In general (with bacteria there are always exceptions) we see that bacteria can survive in very wide temperature ranges. Bacteria can live between 0 and 60 ° Celsius (32 – 122 ° Fahrenheit), however, at a level associated with humans, they grow at their best between 20 and 45 ° Celsius (68 – 113 ° Fahrenheit).

This is because the bacteria that concern us have adapted to our internal bodies to infect and contaminate our bodies. Therefore, the absolute best temperature is 37 ° C (98 ° F).

Humidity (water activity)

Bacteria can grow primarily in moisture-rich environments. In food, bacteria love conditions rich in moisture. Water activity means the amount of water available in a food product. An example of this would be cucumbers, there is a high availability of water in cucumbers, lettuce and celery (95%). Compared to dry spices (5 – 50%). Most bacteria need at least 80% water to survive.

Nutritive content

Just as we as humans need nutrients to survive, so do bacteria. High in nutrients, food is a perfect source of nutrients for bacteria to grow. That is why we need to have very good hygiene standards in the kitchen. Food is an ideal environment for bacteria. Human and animal skin is also an example of a rich source of nutrients for bacteria. Bacteria require sources of carbon, nitrogen, phosphorus, iron, and a host of other minerals.

pH (acidity)

The level of pH or acidity also affects how bacteria grow and how well bacteria can survive in the environment. Bacteria in food have a pH of 5 to 8. This means that things like vinegar are unlikely to allow bacteria to survive.

Lemons are always a popular food when antibacterial properties are mentioned. In fact, pH discourages the growth of bacteria, but it is not a major factor in killing bacteria that occurs through cross contamination. meats, spinach, and milk are within the ideal pH range for bacteria. Yogurt has a pH just below the ideal range and is generally considered less risky than milk because of this.

Oxygen

Bacteria can grow in both oxygen-rich and oxygen-poor environments. This means sealed and unsealed products. Therefore, meals and vacuum packed foods are not without concern. This also means exposing food to the environment and leaving food uncovered allows bacteria to grow.

Hour

The longer bacteria are exposed to the above factors under their ideal conditions, the more established the bacterial cells will be. All of these factors are time dependent, and bacteria can multiply rapidly in 15 to 45 minutes.

Summary

We now know that bacteria can survive temperatures between 0 and 65ºC (32-149ºF).

It grows best at 20 – 45ºC (20 – 113ºF).

They multiply rapidly in 15 to 45 minutes at these ranges.

Moisture-rich environments are favorable.

Can survive pH 3.0 to 7.5

It can survive in poor, oxygen-rich conditions.

As you can see, bacteria are similar to humans in what they need to survive, therefore there are bacteria associated with humans and as a result bacteria found in the food we eat.

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