Question:
Plates of a pasteurizer are fabricated from:
Plates of a pasteurizer are fabricated from:
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AISI 316 stainless steel contains molybdenum, which provides the corrosion resistance required for plate heat exchangers that handle hot dairy fluids, acids, alkalis, and chloride-containing sanitizers.
Updated On: Aug 7, 2026
- AISI 302
- AISI 304
- AISI 310
- AISI 316
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The Correct Option is D
Solution and Explanation
Step 1: Understanding the Concept:
Plate heat exchangers (PHE) used for milk pasteurization consist of thin, corrugated metal plates clamped together in a frame.
These plates must be fabricated from materials that meet strict food contact safety standards and resist corrosion from milk and sanitizing chemicals.
Step 2: Detailed Explanation:
Let us evaluate the suitability of the different grades of stainless steel listed:
1. AISI 302: This is a general-purpose austenitic stainless steel with lower corrosion resistance.
It is not recommended for direct food contact surfaces in dairy processing.
2. AISI 304: This is a common food-grade stainless steel containing 18% chromium and 8% nickel.
While it is widely used for storage tanks, sanitary piping, and receiving vats, it can be susceptible to pitting corrosion in the presence of chlorides (which are present in milk, cooling brines, and sanitizing solutions) at elevated temperatures.
3. AISI 310: This is a heat-resistant stainless steel with high chromium and nickel content, designed for high-temperature furnace applications rather than dairy processing.
4. AISI 316: This grade contains 16--18% chromium, 10--14% nickel, and 2--3% molybdenum.
The addition of molybdenum significantly improves the material's resistance to pitting and crevice corrosion, particularly in chloride-rich environments.
Because pasteurizer plates are subjected to hot milk, hot water, acid and alkaline cleaning solutions, and cooling brines, they require this higher level of corrosion resistance.
Therefore, AISI 316 is the standard material used for fabricating pasteurizer plates.
Step 3: Final Answer:
Therefore, the plates of a pasteurizer are fabricated from AISI 316 stainless steel.
Plate heat exchangers (PHE) used for milk pasteurization consist of thin, corrugated metal plates clamped together in a frame.
These plates must be fabricated from materials that meet strict food contact safety standards and resist corrosion from milk and sanitizing chemicals.
Step 2: Detailed Explanation:
Let us evaluate the suitability of the different grades of stainless steel listed:
1. AISI 302: This is a general-purpose austenitic stainless steel with lower corrosion resistance.
It is not recommended for direct food contact surfaces in dairy processing.
2. AISI 304: This is a common food-grade stainless steel containing 18% chromium and 8% nickel.
While it is widely used for storage tanks, sanitary piping, and receiving vats, it can be susceptible to pitting corrosion in the presence of chlorides (which are present in milk, cooling brines, and sanitizing solutions) at elevated temperatures.
3. AISI 310: This is a heat-resistant stainless steel with high chromium and nickel content, designed for high-temperature furnace applications rather than dairy processing.
4. AISI 316: This grade contains 16--18% chromium, 10--14% nickel, and 2--3% molybdenum.
The addition of molybdenum significantly improves the material's resistance to pitting and crevice corrosion, particularly in chloride-rich environments.
Because pasteurizer plates are subjected to hot milk, hot water, acid and alkaline cleaning solutions, and cooling brines, they require this higher level of corrosion resistance.
Therefore, AISI 316 is the standard material used for fabricating pasteurizer plates.
Step 3: Final Answer:
Therefore, the plates of a pasteurizer are fabricated from AISI 316 stainless steel.
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