What Are Water Activity Levels?
Many things affect how long a type of food can last before it spoils (shelf life). Water activity (aw) is used to express the amount of water available for microbes, enzymes, and chemical reactions inside food. The range of water activity is from 0.0 aw (very dry) to 1.0 aw (pure water). 1.0 aw is considered a high water activity level, while 0.0 aw is considered a low water activity level.
How Do You Store Food Safely?
There are many ways to store food safely. Let’s say you’re going on a backpacking trip and have the options of pre-cooked hamburgers, fresh strawberries, peanut butter, crackers, and raisins. What foods should you leave behind because of bacterial growth and which foods can you take? Foods with higher water activity levels are likely to last shorter because they will have microorganisms living inside. Some microorganisms are microbes and enzymes. To prevent microorganisms from living inside, foods with higher water activity levels than 0.85 aw, potentially hazardous foods, must be kept refrigerated to prevent bacteria growth, like fresh fruit of raw meat. Potentially hazardous foods are foods that can cause illness if their bacterial growth isn’t put to an end.
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How Does Water Activity Affect Food Spoilage? When water molecules touch microbes, the microbes double.
If there are no water molecules to create that other microbe, the microbes will die out. Enzymes (a substance produced by a living organism that is there to bring out a specific reaction) and chemical reactions (a process that ) also need water. If the water activity level is lower than 0.6 aw, then the microorganisms stop growing. Some ways to preserve food, like drying corn, or salting meat work because they control the amount of water activity. Preserving food can evaporate the water (drying) or bind the water up (salting). By evaporating the water, the microorganisms can’t survive. Evaporation and binding water with other substances can both decrease the water activity level of a type of
food. What Are Things That You Can Bind Together To Store Food Safely? One example: salt. Salt, or NaCL (Sodium (Na) + Chloride (CL)) can attract to the polar molecule H2O (water) because each side of these two molecules are partially positive or partially negative. Each salt molecule will attract 8 water molecules. This will help prevent food spoilage because so much of the water is bound up by the salt that the microbes can’t access the water molecules. Once the microbes are out of the way, the food can be stored safely.
Throughout The Awakening, water the main motif serves as a catalyst to the metamorphosis of Edna. During the length of the story Edna goes through a process of changes that coincides with the presence of water. Water serves as a conduit for liberation and empowerment that facilitates the rebirth and even death of Edna. In this essay I will argue that the motif of water represents the continual transformations that occur within Edna throughout the story.
Water: Water is the most important aspect of life on Earth, whether it be for us humans or microbes. Alcamo’s Microbes and Society states that the “microbial cytoplasm is water based”. From this we can see that water absolutely must be present for the microbe to continue its life. Microbes also depend on water to dissolve essential substances that they need to survive.
RTE foods are under scrutiny due to the widespread outbreaks of Listeriosis over the last 2 decades. Post-processing contamination is a common pathway for L. monocytogenes to be introduced into food products because it is so widely spread in the environment (1). Once contamination occurs, L. monocytogenes can proliferate at refrigerated temperatures prior to consumer use of the food (1). RTE foods are typically not further processed after being received by consumers or retailers, which allows for Listeria monocytogenes to proliferate and infect individuals under the right circumstances.
Water is one of the most vital essentials that helps support all of life. In the article “Water Works” by Cynthia Barnett, she talks about the “Growing Vine Street” project in how it has helped clean up the pollution in water. The project changes the flow of the water so it flows into the ground rather than through streets, parking lots, and roofs because it soaks up harmful things that goes into the gutter and cause pollution in many other places. Barnett believes we should upgrade the water system even though it will cost a bunch of money because the current water system is aging and needs to repair, replace, and upgraded. Upgrading the water system will help clean the water more effectively and reduce the amount of pollution in the
We live in an environment full of microorganisms. These organisms may be pathogenic causing serious infections to humans and other living organisms, some just commensals while others are helpful in the food industry. The harmful effect of these organisms is a function of the condition that surrounds them at a particular time. For example, a favorable temperature, and the acidity or alkalinity of the medium in which they find themselves are some of the key factors that helps them multiply well enough to cause infection.
After reviewing both stories, I decided to go with the shorter version of the “So Much Water So Close to Home” story. Although the short and long versions bear some similarities, the differences between them are strong. The long versions gives specific details, which leave no room for thought. While the short passage, the writer lets the readers put their imagination to use, trying to figure out what had, has, and is going to happen in the story. In both versions, the author starts by stating an identical theme, Claire Husband was seating at the table eating. Obviously something is going on between them, because he is eating with aggressiveness, trying to avoid conversation. In cooperation her husband Stuart is very upset stating “Goddam it, why can’t people mind
“Drinking water is like washing out your insides. The water will cleanse the system, fill you up, decrease your caloric load and improve the function of all your tissues.” – Kevin R. Stone --
Humans use water on a daily basis, in everything from drinking, to cleaning, and for recreational uses in pools or waterparks. But the human body itself is the main contester in how it is used. Water is a dissolving essential in vitamins and nutrients for food and for delivering them to cells. Our bodies also use water to flush out toxins, regulate body temperature, and aid our metabolism. The human body is 50-75 percent water, and when that water is lost in digestion or sweat, it needs to be replenished to continue functioning.
“Recreational water illnesses (RWIs) are caused by germs spread by swallowing, breathing in mists or aerosols of, or having contact with contaminated water in swimming pools, hot tubs, water parks, water play areas, interactive fountains, lakes, rivers, or oceans. RWIs can also be caused by chemicals in the water or chemicals that evaporate from the water and cause indoor air quality problems. RWIs may include a wide variety of infections, including gastrointestinal, skin, ear, respiratory, eye, neurologic and wound infections. Many RWIs (skin, ear, eye, respiratory, neurologic, wound, and other infections) are caused by germs that live naturally in the environment (for example, in water and soil)” (Centers for Disease Control and Prevention).
Bacteria are small microorganisms that are found in all environments, they are the building blocks of all life. Bacteria are ubiquitous, they are present everywhere. Bacteria have been present on earth for approximately 3.5 billion years (1, p.1). Bacteria serve a variety of different functions that are ultimately vital to life but can also threaten human life. Bacteria may be small, but our life is dependent upon their activity and growth (1, p.1). Since bacteria are so small and our life is dependent upon their functions and activities, it is important that they are able to divide and reproduce. Bacteria cannot grow and divide unless it is in a favorable environment (2). Each bacterial species has its own specific, optimal requirements for maximal growth and reproduction. In order to deem an environment favorable, it must have the correct oxygen availability, temperature, nutrients, moisture, salinity, and osmotic pressure. Other factors, such as the presence of toxic products can stunt or harm the growth of bacteria.
Food borne illnesses are caused by consuming contaminated foods or beverages. There are many different disease-causing microbes, or pathogens. In addition, poisonous chemicals, or other harmful substances can cause food borne illnesses if they are present in food. More than two hundred and fifty different food borne illnesses have been described; almost all of these illnesses are infections. They are caused by a variety of bacteria, viruses, and parasites that can be food borne. (Center 1)
Observation Day: 1 My first day of observation was on January 20th, 2018. The class began at 8 am and ran until 9 am. I was introduced to Jessica the instructor of the Deep Water Hydrobics class by Elyse Giles who is the Fitness Director at the Athens YMCA. Jessica teaches multiple fitness classes throughout the week. Jessica is the second water aerobics instructor and gets in the water with her participants, unlike Chip, who is another water aerobics instructor, who prefers to stand pool-side and teach.
Lesson Number Lesson Aims 1: Introduce Unit: What do we know about water? Students explore water and access, and how it is treated in Australia. We play a game exploring the different types of water, Students write about water, what they know what they want to know and what interests them. Introduction/ Engagement Session: Students discuss what and water use and access around the world.
Nowadays, refrigeration and freezing had become the most popular method for food preservation. It is a desirable way to preserve food because at low temperatures which around –10°C to –25°C, chemical reactions very slowly thus it will make the bacteria in food hard to survive.