Logout Open In App
Open In App
Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

Chapter 4: Problem 129

How does \((a)\) the air motion and \((b)\) the relative humidity of the environment affect the growth of microorganisms in foods?

Short Answer

Expert verified
Answer: Air motion can influence microorganism growth in foods by affecting evaporation, temperature fluctuations, air circulation, and introducing new microorganisms, which may lead to spoilage or contamination. On the other hand, relative humidity directly affects microorganism growth by influencing the available moisture content in the food. High relative humidity encourages growth, while low relative humidity inhibits it. The effect of relative humidity on microorganism growth depends on the type of organism and the specific environmental conditions.

Step by step solution

01

(Understanding Air Motion and Relative Humidity)

Before discussing their effects on microorganism growth in foods, it is essential to understand the role of air motion and relative humidity. Air motion refers to the movement of air, which can either be natural or artificial. Relative humidity is the amount of water vapor present in the air compared to the maximum amount the air could hold at the same temperature, expressed as a percentage.
02

(The Effect of Air Motion on Microorganism Growth in Foods)

Air motion can influence the growth of microorganisms in foods in several ways: 1. Increased air motion can cause faster evaporation, leading to a decrease in the available moisture for microorganisms to grow and thrive. This reduces the rate of growth for certain microorganisms that require high moisture levels. 2. Air motion can also cause fluctuations in temperature, which might influence the growth of specific microorganisms that are sensitive to temperature variations. 3. Faster air circulation can help remove volatile compounds produced by microorganisms, potentially inhibiting or slowing down their growth rate. 4. Air motion can also introduce new microorganisms into the food, potentially leading to spoilage or even pathogenic contamination.
03

(The Effect of Relative Humidity on Microorganism Growth in Foods)

Relative humidity can also significantly influence the growth of microorganisms in foods: 1. High relative humidity provides more available moisture for microorganisms to grow. The increased moisture content in the air can be easily absorbed by the food, which encourages the growth of microorganisms, including molds, yeasts, and bacteria. 2. Low relative humidity may slow down the growth of microorganisms by reducing the available moisture content in the food. This drier environment may cause the food to become preserved, thus inhibiting the growth of certain microorganisms. 3. It is essential to note that different microorganisms have varying optimal relative humidity levels for growth. Therefore, the effect of relative humidity on microorganism growth in foods is largely dependent on the type of organism present and the food's specific environmental conditions. In conclusion, both air motion and relative humidity play essential roles in the growth of microorganisms in foods. By understanding these factors and their effects on microorganism growth, optimal food storage conditions can be established to minimize food spoilage and reduce the risk of foodborne illnesses.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Thick slabs of stainless steel $(k=14.9 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\( and \)\left.\alpha=3.95 \times 10^{-6} \mathrm{~m}^{2} / \mathrm{s}\right)\( and copper \)(k=401 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\( and \)\left.\alpha=117 \times 10^{-6} \mathrm{~m}^{2} / \mathrm{s}\right)$ are placed under an array of laser diodes, which supply an energy pulse of \(5 \times 10^{7} \mathrm{~J} / \mathrm{m}^{2}\) instantaneously at \(t=0\) to both materials. The two slabs have a uniform initial temperature of \(20^{\circ} \mathrm{C}\). Determine the temperatures of both slabs at $5 \mathrm{~cm}\( from the surface and \)60 \mathrm{~s}$ after receiving an energy pulse from the laser diodes.

Consider a cubic block whose sides are \(5 \mathrm{~cm}\) long and a cylindrical block whose height and diameter are also \(5 \mathrm{~cm}\). Both blocks are initially at \(20^{\circ} \mathrm{C}\) and are made of granite $\left(k=2.5 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\right.\( and \)\left.\alpha=1.15 \times 10^{-6} \mathrm{~m}^{2} / \mathrm{s}\right)$. Now both blocks are exposed to hot gases at \(500^{\circ} \mathrm{C}\) in a furnace on all of their surfaces with a heat transfer coefficient of $40 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}$. Determine the center temperature of each geometry after 10 , 20 , and \(60 \mathrm{~min}\). Solve this problem using the analytical oneterm approximation method.

Consider a 7.6-cm-long and 3-cm-diameter cylindrical lamb meat chunk $\left(\rho=1030 \mathrm{~kg} / \mathrm{m}^{3}, c_{p}=3.49 \mathrm{~kJ} / \mathrm{kg} \cdot \mathrm{K}\right.\(, \)k=0.456 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}, \alpha=1.3 \times 10^{-7} \mathrm{~m}^{2} / \mathrm{s}$ ). Fifteen such meat chunks initially at \(2^{\circ} \mathrm{C}\) are dropped into boiling water at \(95^{\circ} \mathrm{C}\) with a heat transfer coefficient of $1200 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}$. The amount of heat transfer during the first \(8 \mathrm{~min}\) of cooking is (a) \(71 \mathrm{~kJ}\) (b) \(227 \mathrm{~kJ}\) (c) \(238 \mathrm{~kJ}\) (d) \(269 \mathrm{~kJ}\) (e) \(307 \mathrm{~kJ}\)

It is claimed that beef can be stored for up to two years at $-23^{\circ} \mathrm{C}\( but no more than one year at \)-12^{\circ} \mathrm{C}$. Is this claim reasonable? Explain.

During a fire, the trunks of some dry oak trees $\left(k=0.17 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\right.\( and \)\left.\alpha=1.28 \times 10^{-7} \mathrm{~m}^{2} / \mathrm{s}\right)$ that are initially at a uniform temperature of \(30^{\circ} \mathrm{C}\) are exposed to hot gases at \(600^{\circ} \mathrm{C}\) for a period of \(4 \mathrm{~h}\), with a heat transfer coefficient of \(65 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\) on the surface. The ignition temperature of the trees is \(410^{\circ} \mathrm{C}\). Treating the trunks of the trees as long cylindrical rods of diameter $20 \mathrm{~cm}$, determine if these dry trees will ignite as the fire sweeps through them. Solve this problem using the analytical one-term approximation method.
See all solutions

Recommended explanations on Physics Textbooks

Electric Charge Field and Potential

Read Explanation

Nuclear Physics

Read Explanation

Quantum Physics

Read Explanation

Atoms and Radioactivity

Read Explanation

Wave Optics

Read Explanation

Torque and Rotational Motion

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free