The process time required at 115°C for 1 log cycle reduction of a particular microorganism having D{121} = 3 min and z = 15°C is : / D{121} = 3 मिनट और z = 15°C वाले एक विशेष सूक्ष्मजीव के 1 log चक्र अपचयन (reduction) के लिए 115°C पर आवश्यक प्रक्रिया समय क्या है?

(4) 7.53 min / 7.53 मिनट Explanation (English): Calculation of D-value at alternate processing temperature: (A) 10.04 min is an incorrect calculation. (B) 11.94 min is an incorrect calculation. (C) 17.15 min would correspond to a much smaller z-value. (D) Process time for 1 log cycle reduction equals the decimal reduction time at 115°C (D{115}). The thermal relationship between D-values at two temperatures is: {10}({DT}{D{ref}}) = {T{ref} - T}{z}. Here, T{ref} = 121°C, D{121} = 3 min, T = 115°C, and z = 15°C. Substituting the values: {10}({D{115}}{3}) = (121 - 115/15) = (6/15) = 0.4. Therefore, {D{115}}{3} = 10^{0.4} ≈ 2.511886 D{115} = 3 × 2.511886 = 7.5356 ≈ 7.53 min. Therefore, option 4 (7.53 min) is the correct answer. व्याख्या (हिंदी): विभिन्न तापमानों पर D-मान की गणना: (A) 10.04 मिनट अमान्य परिणाम है। (B) 11.94 मिनट अमान्य मान है। (C) 17.15 मिनट गलत गणना है। (D) 1 log चक्र अपचयन के लिए आवश्यक समय 115°C पर D-मान (D{115}) के बराबर होता है। तापीय विनाश सूत्र: {10}((D₁/D₂)) = (T₂ - T₁/z)। यहाँ T₂ = 121°C, D₂ = 3 min, T₁ = 115°C, तथा z = 15°C है। मान रखने पर: {10}({D{115}}{3}) = (121 - 115/15) = (6/15) = 0.4। अतः {D{115}}{3} = 10^{0.4} ≈ 2.5119 D{115} = 3 × 2.5119 = 7.5356 ≈ 7.53 मिनट। अतः विकल्प 4 सही उत्तर है।

The process time required at 115°C for 1 log cycle reduction of...

All Subjects Fluid Milk Processing, Dairy Products Manufacture, Sensory Evaluation & Packaging Dairy Process Equipment, Plant Design & Computer Applications Fluid Mechanics, Refrigeration, Heat Transfer, Mechanical & Electrical Engineering

Q.101

ICAR AIEEA PG Dairy Technology 09 July 2023 (Shift 1) Paper

MCQ (Single Correct)

The decimal reduction time (D value) depends on

which of the following ?

दशमलव अपचयन समय (D मान / Decimal reduction time) निम्नलिखित में से किस पर निर्भर करता है?

No. of microorganisms present in foods खाद्य पदार्थों में उपस्थित सूक्ष्मजीवों की संख्या पर Time of heating गर्म करने के समय पर Temperature of heating गर्म करने के तापमान पर Pressure applied लागू किए गए दबाव पर

Characteristics and dependencies of decimal reduction time ($D$-value):

Initial microbial load affects total sterilizing time required ($F$), but the D-value itself represents the time for a 1-log ($90\%$) fraction reduction and is independent of initial microbial population.
Heating duration is the variable during processing, not a parameter governing the intrinsic D-value constant.
The D-value is an intrinsic kinetic property that depends directly on the heating temperature (as well as specific organism type and medium composition). According to Bigelow's thermal death time model, higher temperatures exponentially accelerate death kinetics and decrease the D-value.
Moderate hydrostatic pressure during thermal processing does not dictate thermal D-values in conventional systems.

Therefore, option 3 (Temperature of heating) is the correct answer.

डेसीमल रिडक्शन टाइम (D-मान) की निर्भरता:

खाद्य पदार्थ में सूक्ष्मजीवों की प्रारंभिक संख्या कुल प्रसंस्करण समय ($F$) को प्रभावित करती है, लेकिन D-मान स्वयं $90\%$ कमी हेतु लगने वाला दर स्थिरांक है जो प्रारंभिक संख्या पर निर्भर नहीं करता।
गर्म करने का समय प्रक्रिया की अवधि है।
मान सीधे गर्म करने के तापमान (Temperature of heating) पर निर्भर करता है। जैसे-जैसे तापमान बढ़ता है, सूक्ष्मजीवों के विनाश की दर तेज होती है और D-मान घटता जाता है।
साधारण तापीय पाश्चुरीकरण में प्रयुक्त दबाव D-मान को सीधे निर्धारित नहीं करता।

अतः विकल्प 3 सही उत्तर है।

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.102

ICAR AIEEA PG Dairy Technology 09 July 2023 (Shift 1) Paper

MCQ (Single Correct)

The process time required at $115^\circ\text{C}$ for $1\text{ log}$ cycle reduction of a particular microorganism having $D_{121} = 3\text{ min}$ and $z = 15^\circ\text{C}$ is :

$D_{121} = 3\text{ मिनट}$ और $z = 15^\circ\text{C}$ वाले एक विशेष सूक्ष्मजीव के $1\text{ log}$ चक्र अपचयन (reduction) के लिए $115^\circ\text{C}$ पर आवश्यक प्रक्रिया समय क्या है?

$10.04\text{ min}$ $10.04\text{ मिनट}$ $11.94\text{ min}$ $11.94\text{ मिनट}$ $17.15\text{ min}$ $17.15\text{ मिनट}$ $7.53\text{ min}$ $7.53\text{ मिनट}$

Calculation of D-value at alternate processing temperature:

$10.04\text{ min}$ is an incorrect calculation.
$11.94\text{ min}$ is an incorrect calculation.
$17.15\text{ min}$ would correspond to a much smaller $z$-value.
Process time for $1\text{ log}$ cycle reduction equals the decimal reduction time at $115^\circ\text{C}$ ($D_{115}$). The thermal relationship between D-values at two temperatures is: $\log_{10}\left(\frac{D_T}{D_{\text{ref}}}\right) = \frac{T_{\text{ref}} - T}{z}$. Here, $T_{\text{ref}} = 121^\circ\text{C}$, $D_{121} = 3\text{ min}$, $T = 115^\circ\text{C}$, and $z = 15^\circ\text{C}$. Substituting the values: $\log_{10}\left(\frac{D_{115}}{3}\right) = \frac{121 - 115}{15} = \frac{6}{15} = 0.4$. Therefore, $\frac{D_{115}}{3} = 10^{0.4} \approx 2.511886 \implies D_{115} = 3 \times 2.511886 = 7.5356 \approx 7.53\text{ min}$.

Therefore, option 4 ($7.53\text{ min}$) is the correct answer.

विभिन्न तापमानों पर D-मान की गणना:

$10.04\text{ मिनट}$ अमान्य परिणाम है।
$11.94\text{ मिनट}$ अमान्य मान है।
$17.15\text{ मिनट}$ गलत गणना है।
$1\text{ log}$ चक्र अपचयन के लिए आवश्यक समय $115^\circ\text{C}$ पर D-मान ($D_{115}$) के बराबर होता है। तापीय विनाश सूत्र: $\log_{10}\left(\frac{D_1}{D_2}\right) = \frac{T_2 - T_1}{z}$। यहाँ $T_2 = 121^\circ\text{C}$, $D_2 = 3\text{ min}$, $T_1 = 115^\circ\text{C}$, तथा $z = 15^\circ\text{C}$ है। मान रखने पर: $\log_{10}\left(\frac{D_{115}}{3}\right) = \frac{121 - 115}{15} = \frac{6}{15} = 0.4$। अतः $\frac{D_{115}}{3} = 10^{0.4} \approx 2.5119 \implies D_{115} = 3 \times 2.5119 = 7.5356 \approx 7.53\text{ मिनट}$।

अतः विकल्प 4 सही उत्तर है।

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.103

ICAR AIEEA PG Dairy Technology 09 July 2023 (Shift 1) Paper

MCQ (Single Correct)

The conductive heat transfer is guided by

which of the following laws ?

चालन ऊष्मा स्थानांतरण (conductive heat transfer) निम्नलिखित में से किस नियम द्वारा निर्देशित होता है?

Fourier's law फोरियर का नियम Stefan's law स्टीफन का नियम Newton's law न्यूटन का नियम Rittinger's law रिटिंगर का नियम

Q.104

ICAR AIEEA PG Dairy Technology 09 July 2023 (Shift 1) Paper

MCQ (Single Correct)

Which of the following metals is having the highest value of thermal conductivity ?

निम्नलिखित में से किस धातु का तापीय चालकता (thermal conductivity) मान सबसे अधिक है?

Copper तांबा Silver चांदी Aluminium एल्युमीनियम Stainless steel स्टेनलेस स्टील

Q.105

ICAR AIEEA PG Dairy Technology 09 July 2023 (Shift 1) Paper

MCQ (Single Correct)

Calculate the power required for homogenizer if flow rate is $10,000\text{ lph}$ and homogenizing pressure is $250\text{ bar}$.

यदि प्रवाह दर $10,000\text{ lph}$ (लीटर प्रति घंटा) और समांगीकरण दबाव $250\text{ bar}$ है, तो होमोजिनाइज़र के लिए आवश्यक शक्ति (power) की गणना कीजिए।

$50\text{ kW}$ $50\text{ kW}$ $56\text{ kW}$ $56\text{ kW}$ $90\text{ kW}$ $90\text{ kW}$ $70\text{ kW}$ $70\text{ kW}$

Fluid Milk Processing, Dairy Products Manufacture, Sensory Evaluation & Packaging

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Packaging Materials & Systems: Flexible Laminates, Aseptic Packaging, MAP, Vacuum Packaging & Quality Evaluation Thermal Processing of Fluid Milk: LTLT, HTST Pasteurization, UHT, Sterilization & ESL Systems Active Technology of Frozen Dairy Desserts: Ice Cream Mix Formulation, Freezing, Overrun, Hardening & Novelties Dairy By-Product Utilization & Whey Processing: Casein, Caseinates, Whey Powder, WPC, WPI & Lactose Recovery Sensory Evaluation of Dairy Products: Discrimination Tests, Hedonic Scaling, Scoring Systems & Flavor Defect Profiling Concentrated Milks: Evaporated Milk, Sweetened Condensed Milk, Standardization & Pilot Sterilization Fluid Milk Reception, Chilling, Clarification, Standardization & Homogenization Ghee Technology: Traditional, Cream-Butter, Pre-Stratification & Continuous Methods, Packaging & AGMARK Dried Milks: Roller & Spray Drying, Atomization, Powder Properties, Instantization & Specialty Infant Formulas Cheese Manufacture: Coagulation, Curd Handling, Cheddaring, Pressing, Salting & Curing of Hard & Semi-Hard Cheeses Butter Technology: Batch Churning, Continuous Butter Making (CBM), Working, Salting & Rheology Traditional Heat-Desiccated & Acid-Coagulated Indian Dairy Products: Khoa, Paneer, Chhana & Their Sweets Membrane Filtration in Dairy Processing: Reverse Osmosis (RO), Nanofiltration (NF), Ultrafiltration (UF) & Microfiltration (MF) Soft, Acid-Coagulated & Mold-Ripened Cheeses: Cottage, Mozzarella, Camembert, Roquefort & Fresh Cheeses Technology of Fermented & Probiotic Milks: Dahi, Yoghurt, Cultured Buttermilk, Lassi, Kefir & Koumiss Technology of Fat-Rich Products: Cream Separation, Processing, Neutralization & Cream Varieties Traditional Fermented, Fat-Rich & Frozen Indian Dairy Confections: Shrikhand, Rabri, Kulfi & Ghee Residue

Dairy Process Equipment, Plant Design & Computer Applications

11 Topics

Process Automation & Computer Applications: PLC, SCADA, PID Controllers, Digital Sensors, Data Acquisition & Plant Informatics Fluid Handling Equipment: Sanitary Pumps (Centrifugal, Rotary, Positive Displacement), Sizing, NPSH & Cavitation Plate Heat Exchangers (PHE) & Tubular Heat Exchangers: Corrugation, Regeneration Efficiency & Gasket Materials Spray Dryers & Atomization Systems: Pressure Nozzles, Rotary Atomizers, Drying Chambers, Cyclones & Bag Filters Dairy Plant Layout & Site Selection: Master Planning, Space Requirements, Clean Room Zoning & Service Distribution Thermal Evaporators & Vapor Compression Systems: Falling Film, Multi-Effect, TVR, MVR & Steam Economy Centrifugal Clarifiers, Cream Separators & Bactofuges: Disc Bowl Geometry, Skimming Efficiency & Desludging High-Pressure Milk Homogenizers: Piston Mechanics, Valve Geometry, Two-Stage Homogenization & Power Calculation Clean-In-Place (CIP) Systems: Spray Balls, Solution Cycling, Flow Dynamics, Temperature-Concentration Control & Sanitization Scraped Surface Freezers & Cheese Processing Equipment: Continuous Ice Cream Freezers, Mechanized Cheese Vats & Block Formers Sanitary Piping, Valves, Fittings & Flow Diversion Systems: Pipe Friction, Head Loss & Layout Principles

Fluid Mechanics, Refrigeration, Heat Transfer, Mechanical & Electrical Engineering

10 Topics

Fluid Statics & Dynamics: Viscosity, Rheology of Dairy Fluids, Reynolds Number, Laminar vs Turbulent Flow & Bernoulli's Theorem Mechanical Power Transmission & Machine Elements: Belts, Pulleys, Gears, Chain Drives, Shafts, Couplings & Bearings Refrigeration Principles & Vapor Compression Systems: P-h Diagrams, COP, Eco-Friendly Refrigerants & Compressors Electrical Engineering & Motors: 3-Phase AC Circuits, Power Factor Correction, Induction Motors, Starters & Variable Frequency Drives (VFD) Conduction & Insulation: Fourier's Law, Steady-State Heat Conduction, Composite Pipe Insulation & Lagging Materials Dairy Refrigeration Equipment & Cold Storage: Condensers, Expansion Valves, DX Evaporators, Ice Bank Tanks (IBT) & Chilled Water Systems Mass Transfer, Psychrometry & Air Conditioning: Psychrometric Properties, Humidity Ratio, Enthalpy & Drying Chamber Kinetics Convection, Radiation & Overall Heat Transfer: Forced Convection, Nusselt Number, LMTD, Radiation & Fouling Factor Steam Generation & Boilers: Boiler Types, Mountings, Accessories, Steam Enthalpy, Steam Traps & Feed Water Softening Materials of Construction & Corrosion Control: Stainless Steel Metallurgy (SS 304, SS 316), Passivation, Pitting & Crevice Corrosion

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ICAR AIEEA PG Dairy Technology 09 July 2023 (Shift 1) Paper

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Fluid Milk Processing, Dairy Products Manufacture, Sensory Evaluation & Packaging

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Fluid Mechanics, Refrigeration, Heat Transfer, Mechanical & Electrical Engineering

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