Tortora, Funke & A Case Study

Birdseye was right! Before quick-freezing came along, foods were frozen at a fairly slow rate. This caused large ice crystals to form, which ruptured the cell membranes of the food. When the food was defrosted, the ice crystals melted and water would leak out, taking with it the food’s flavor and texture.

Bacterial endospores are highly resistant structures that can withstand many forms of treatments, including heat and UV (Atrih & Foster, 2002), and this characteristic is facilitated by their unique spore structure. Bacterial capsules play an important role in the virulence of bacteria for their host, and enable bacterial cells to evade host defense mechanisms and survive hostile environments. The structure and function of endospores and capsules work specifically to benefit the microbial cell; furthermore, various physiological changes occur in these structures as a result of environmental stress (Sahin, Yong, Driks, & Mahadevan, 2012). The specific mechanism of these physiological changes, the types of environmental stresses that cause the changes, and how these correlate with endospore and capsular structure and function are essential to the understanding of this topic.

Responses to environmental stress have been described in Escherichia coli and Bacillus subtilis. These studies have shown that bacteria display elaborate responses to environmental stress which improve survival by altering bacterial physiology. The SOS response is induced when bacteria are threatened by the presence of agents that cause DNA damage which enhance the bacterium’s ability to repair DNA and inhibit cell division,[26]. The stringent response, in the face of nutrient limitation, decreases protein synthesis and stimulates amino acid biosynthesis when protein synthesis substrates are scarce,[27-28]. Heat shock factors are expressed at raised temperatures that break down and restructure denatured proteins and also restore alterations to chromosomal topology that occur as a result of temperature,[29-30]. Finally components of the cold shock response have been shown to alter mRNA secondary structures, formed as a result of low temperature, which hinder the translational machinery,[31, 31].

So why would these foods spoil if they weren’t refrigerated? Pathogenic bacteria grows rapidly in temperatures above 4.4°C (40°F). This type of bacteria does not affect the smell, taste, or appearance of the food, making it difficult to determine whether or not the pathogens are present. By refrigerating foods at the correct temperature, you are eliminating the chances of these harmful pathogens growing in your food and contaminating them. For example, if you accidentally left a jug of milk on the counter overnight it would become warm and develop a rancid odor. If you were to drink it, the chances of you getting a foodborne illness would be high considering that the harmful pathogens had time to grow. Spoilage bacteria can also grow at low temperatures, however they cause foods to develop disgusting odors and appearances. Most people would not choose to eat these foods, but if they did they would most likely not become ill. If I were

Freezing the food may kill some of the bacteria and inhibit growth. (F. W. Schofield, 1945) Treating with heat has become the basic form of treating Salmonella, but in some foods cells can become heat resistance, such as the case with peanut butter. Antibodies and vaccines have been developed that protect children from bacterial infection caused by Salmonella. The largest preventive measure taken thus far has been the collaborative approach in food safety handling and processing, applying preventive measures in food safety in all stages of the food supply chain. Further strategies for reducing the spread of Salmonella include educating the consumers, foodservice establishments, and food workers on public

These two method of microbial control are used for different purpose, while sterilization is used to keep instruments, equipment, materials and objects free from harmful microorganisms, viruses and bacterial endospores, pasteurization is used keep food and beverages from spoiling by killing pathogens and reducing the number of spoilage microorganism. During the pasteurization of food products, not all microorganism is destroyed, thermoduric and thermophilic prokaryotes can survive. However, they do not represent a health risk for consumers because theses prokaryotes are not commonly pathogenic. Also, pasteurized foods are refrigerated right away and stored until consumption.

Recently, persistence of foodborne bacterial pathogens in food processing environments has become of great impacting hazards to the public health as well as increases risk of microbial food contamination (Pricope et al., 2013; Larsen et al.,

Leaving food out too long at room temperature can cause bacteria (such as Staphylococcus aureus, Salmonella Enteritidis, Escherichia coli O157:H7, and Campylobacter) to grow to dangerous levels that can cause illness. Bacteria grow most rapidly in the range of temperatures between 40 °F and 140 °F, doubling in number in as little as 20 minutes. This range of temperatures is often called the "Danger Zone." Pathogens grow especially fast between 70°F and 125°F.

Chilly adjusted (psychrophilic and psychrotrophic) microorganisms are recognized from mesophiles which their capacity to develop at low temperatures. They are generally conveyed in nature. Their reaction to high temperatures was demonstrated to be disturbance in protein union by failure of RNA development, modifications of the structure of nucleic acids, inactivation of thermo labile catalysts, enactment of lytic chemicals, changes of the cell morphology, hindrance of cell division and instigation of warmth stun proteins. At low temperatures, among other physiological attributes, psychrophiles and psychrotrophs have slower metabolic rates and higher synergist efficiencies than mesophiles. The Cold-adjusted microorganisms have a significant

In general, bacteria are found lurking around in each and every day of life. However, the improper handling of meat is seen to cause and generate the growth of bacteria to unsafe and critical levels. The elements involve time, temperature, dampness, and supplements (sustenance). Microscopic organisms starts to develop on meat when the temperature of it is somewhere around 40 and 140 degrees Fahrenheit (Wagner, 2008). This is on the grounds that most microbes flourish at these temperatures and are most alive inside of this reach. On the off chance that solidified meat is forgotten in room temperature after some time, the meat will start to defrost making dampness that the microscopic organisms needs to develop. Defrosting meat turns into the supplement that the microorganisms needs to develop, subsequently; why the microscopic organisms starts to develop on the meat. Over the long haul the microscopic organisms’ spreads more until extremely risky levels are come to.

In the experiment, it was tested that bacteria will be most effectively eliminated when using hot water during the hand washing procedure. It was predicted that if the subjects use a higher temperature of water while washing hands, then the percent decrease of bacteria will be greater in hands washed in hot water as compared to those washed in cold. In the experiment, two groups were created one being the control group made from two test subjects and one other named the experimental made from 3 test subjects. The control group was the group that used soap and normal(room) temperature water, while the experimental used hot water (110-120 degrees).

The purpose of this experiment was to examine how microbial spoilage effected washed shelled eggs after refrigeration. In this experiment eggs were exposed to room temperature over the course of 14 days to see if the contents of the egg (yolk and egg white’s) would contain microbial contamination by examining it on TSA plates. Washed eggs were free of bacteria through the course of 13 days. Isolated colonies were seen at day 15 but the results could have been observed due to cross contamination.

NILSSON, LENA, James D Oliver, and STAFFAN KJELLEBERG. "Resuscitation of Vibrio Vulnificus from the Viable but Nonculturable State." JOURNAL OF BACTERIOLOGY 173.16 (1991): 5054-059. American Society for Microbiology. Web. 1 Dec. 2015. According to this article, Vibrio vulnificus is a gamma-negative bacteria occurring all over the world in coastal areas. Continuities consistently affect the adaptation of this pathogen. These constant changes are mostly deemed on temperature and control the ability of this pathogen to survive in places that are partly enclosed by littoral bodies of salted water. These bacteria which require salt nutrients have also been known to enter nonculturable state when temperatures shift from hot to cold or cold to hot.

Finally, among other methods, the company is considering some form of heat treatment to kill bacteria while maintaining integrity and optimal

Forming healthy cooking habits can be difficult to accomplish, but simple tips can help avoid preventable sicknesses. Simple advice such as cleanliness, proper cooking temperatures, and personal hygiene are essential when practicing good food safety. Cleaning vegetables under cold running water is important, because it helps to wash away the layer of bacteria and dirt before eating. One myth about preparing food is washing meats before cooking. Washing meats can actually spread bacteria across counters and sinks (FoodSafety.gov, n.d.). When the meat is put in the oven, the heat, when at the appropriate temperature, kills the bacteria. Proper cooking and storage temperatures help prevent bacteria from multiplying. Temperatures above 140 degrees Fahrenheit kill most bacteria, but food storage becomes dangerous when stored in temperatures between 41 – 140 (Nadakavukaren, 2011).