Quantcast Factors influencing the growth of microorganisms - Preservation of Foods

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
(3)  By control of one or more unfavorable environmental conditions such as
nutrients, moisture, pH, or temperature. The greater the number of conditions that are
unfavorable means the longer the delay of the beginning of cell growth.
(4)
By damage to organisms through processing methods such as heat or
irradiation.
1-17. FACTORS INFLUENCING GROWTH OF MICROORGANISM
There are several factors that influence the growth of microorganisms: nutrition,
oxygen, pH, temperature, and moisture. Lack of food retards bacterial growth, and
growth is favored by a sufficient quantity of the proper kind of food. Moisture is required
to carry foods in solution into the cell, to carry wastes in solution away from the cell, and
to maintain the moisture content of the cytoplasm. Temperature has a profound
influence on the growth rate of microorganisms. Microorganisms subjected to adverse
temperatures are either destroyed or are not able to multiply. The optimum temperature
of a microorganism is the temperature that provides for the most rapid growth of that
microorganism. The pH of the medium in which microorganisms grow exerts a
considerable influence on their rate of growth. All microorganisms have an optimum pH
at which they grow best. Most species of bacteria have an optimum pH between 6.0
and 8.5. Molds will grow in a pH range between 2.0 to 8.5. Yeasts have an optimum
pH range from 5.5 to 6.5.
1-18. NUTRITION
Nutrients or foods are substances which are outside the cell and which, upon
entering a cell after passing across the cell membrane, can be used by the cell for
building material or for obtaining energy. Food requirements of bacteria show great
variations from species to species. Some organisms can obtain all their food
requirements from inorganic matter while others need many complex organic
compounds. Although any one species may be able to use only a small number of
materials as sources of food, bacteria as a group are able to utilize all the naturally
occurring organic compounds as well as many inorganic substances.
a. Requirements. Bacteria require foods for the same purposes, as do other
forms of life, namely, as sources of material for cellular synthesis and for energy in
order to perform these synthetic processes. Requirements include carbohydrates
(sugar, starches, and celluloses), a source of nitrogen, vitamins, water, and a source of
energy.
b. Sources. The majority of bacteria species use naturally occurring organic
materials such as carbohydrates, proteins, fats, and so forth, not only as sources of carbon,
hydrogen, oxygen, and nitrogen but also for the energy needed to synthesize these
materials into protoplasm (that material referred to as the physical basis of life and
which is common to all living cells). The requirements of most bacteria for inorganic
materials can be satisfied by salts containing sodium, potassium, calcium, magnesium,
MD0703
1-16



Medical News
Prolonged Remission Now Possible in Lupus (CME/CE)
(MedPage Today) -- Less organ damage when remission is complete...
medpagetoday.com
Sacroiliitis Common But May Be Asymptomatic in JSpA (CME/CE)
(MedPage Today) -- Screening recommended for HLA-B27-positive, high-CRP patients...
medpagetoday.com
Primary Care Compensation Rising Faster Than Specialists, But ?
(MedPage Today) -- MGMA report puts primary care at nexus...
medpagetoday.com
Childhood cancer cells drain immune system's batteries
Cancer cells in neuroblastoma contain a molecule that breaks down...
medicalxpress.com
Slippery Slope: Does Convenience Trump Safety with NOACs?
(MedPage Today) -- Celebrities tout ease of new anticoagulants, but...
medpagetoday.com
Slippery Slope: The Master of the Game
(MedPage Today) -- Gregory Lip, MD, practices in England, but...
medpagetoday.com
Slippery Slope: FDA Reviewer Questions Eliquis Mortality Claim
(MedPage Today) -- Trial data from more than 300 patients...
medpagetoday.com
Slippery Slope: How the NOAC Series Was Produced
(MedPage Today) -- Reporters reviewed approval documents, adverse event, and...
medpagetoday.com
Report Clarifies Management of H. Pylori Gastritis
(MedPage Today) -- Eradication therapy should be first-line treatment, panel...
medpagetoday.com
PodMed: A Medical News Roundup From Johns Hopkins (with audio)
(MedPage Today) -- This week's topics include a balloon for...
medpagetoday.com
D.C. Week: Health Spending to Rise Nearly 6%
(MedPage Today) -- CMS gives 10-year forecast, salutes Medicare and...
medpagetoday.com
Researchers reveal climbing a tree can improve cognitive skills
Climbing a tree and balancing on a beam can dramatically...
medicalxpress.com
Homosexual Necrophiliac Duck Opera: That's Improbable!
(MedPage Today) -- And the pitfalls of sword swallowing revisited...
medpagetoday.com
Treatment targets not met by most older patients with diabetes
(HealthDay)—Only one-third of American seniors with diabetes have their disease...
medicalxpress.com
'Thrifty phenotype' leads to less weight loss in obese
(HealthDay)—For obese individuals, energy expenditure during fasting and response to...
medicalxpress.com
Most obstetricians screen for group B strep at 35 to 37 weeks
(HealthDay)—Almost all obstetricians collect group B streptococcus screening samples, but...
medicalxpress.com
Accuracy, timing of pre-op lung CA evaluation can be improved
(HealthDay)—For suspected lung cancer patients, the thoroughness, accuracy, and timeliness...
medicalxpress.com
Stay safe when temperatures rise
(HealthDay)—Extremely hot weather can be deadly if you don't take...
medicalxpress.com
CDC: 20 percent of U.S. adults have a disability
(HealthDay)—More than 50 million Americans live with a physical or...
medicalxpress.com
Test set performance indicators correlate well with clinical audit
(HealthDay)—Some performance indicators for mammography test sets are associated with...
medicalxpress.com
 


Privacy Statement - Copyright Information. - Contact Us

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +