VELAMMAL VIDHYASHRAM
MARAIMALAI NAGAR
SENIOR SCHOOL
CERTIFICATE EXAMINATION
CHEMISTRY
Name: Jayaprakash.G
Class: XII - A
Roll No:
Group: Computer Science
BONAFIDE CERTIFICATE
This is to certify that this Chemistry project on the topic "Potassium bisulfate as a food
preservative" has been successfully completed by Jayaprakash.G of class XII-A, Roll No.
…………………… at Velammal Vidhyashram, Maraimalai Nagar, for the partial fulfillment of
this project as a part of Senior School Certificate Examination - CBSE, New Delhi, for the
academic year 2025 - 2026.
Date: ……………………..
Signature of the Principal Signature of the Guide
Signature of the Internal Examiner Signature of the External Examiner
ACKNOWLEDGEMENT
I would like to express my heartfelt gratitude to my chemistry teacher for his/her
continuous support and guidance throughout the completion of this investigatory project. I
am also thankful to the principal, Velammal Vidhyashram, for providing the facilities and
encouragement to carry out this research. Lastly, I thank my family and friends for their
moral support.
TABLE OF CONTENTS
1. Abstract
2. Introduction
3. Aim & Hypothesis
4. Theoretical Background
5. Scientific Principle
6. Materials and Equipment Required
7. Detailed Experimental Procedure
8. Observations & Data Recording
9. Mathematical Calculations
10. Data Analysis & Interpretation
11. Results & Comparison
12. Conclusion & Summary
13. Limitations & Challenges
14. Safety Measures & Precautions
15. Real-World Applications
16. Future Scope & Advancements
17. References & Bibliography
Abstract
This project investigates the use of potassium bisulfate as a food preservative. It explores its
chemical properties, effects on microbial growth, and safety as an additive in packaged
foods. The objective is to determine its efficacy compared to common preservatives like
sodium benzoate.
Introduction
Food preservation is essential for prolonging shelf life and preventing spoilage.
Preservatives inhibit microbial activity that leads to food degradation. Potassium bisulfate
(KHSO4) is an acidic salt known for its antimicrobial properties. This project delves into its
role as a preservative in various food items.
Aim & Hypothesis
Aim: To study the efficiency of potassium bisulfate as a food preservative.
Hypothesis: Potassium bisulfate reduces microbial growth and extends shelf life when used
in small quantities.
Theoretical Background
Potassium bisulfate is a chemical compound with the formula KHSO4. It dissociates in
water, releasing hydrogen ions, which lowers pH and creates an acidic environment that
inhibits microbial growth. It is used in winemaking and other food industries.
Scientific Principle
The action of potassium bisulfate is based on lowering pH, making the medium inhospitable
for microbial life. The acidic environment denatures enzymes essential for microbial
metabolism, thereby preserving food.
Materials and Equipment Required
- Potassium bisulfate
- Food samples (fruit juices, jams)
- Petri dishes
- Nutrient agar
- Incubator
- Measuring instruments (pipettes, beakers)
- pH meter
Detailed Experimental Procedure
1. Prepare food samples with and without potassium bisulfate.
2. Pour equal volumes into sterile containers.
3. Inoculate with a known microbial strain.
4. Incubate at 37°C.
5. Monitor for microbial growth over 7 days.
6. Measure pH and record colony count.
Observations & Data Recording
Samples treated with potassium bisulfate showed significantly less microbial growth than
untreated samples. The pH was also lower in treated samples.
Mathematical Calculations
Percent Inhibition = [(Colony count in control - Colony count in test) / Colony count in
control] × 100
Example: (200 - 50) / 200 × 100 = 75% inhibition
Data Analysis & Interpretation
Data supports the hypothesis that potassium bisulfate inhibits microbial growth. Its effect is
comparable to commercial preservatives.
Results & Comparison
Potassium bisulfate was nearly as effective as sodium benzoate. Both preservatives showed
over 70% microbial growth reduction.
Conclusion & Summary
Potassium bisulfate is a viable food preservative. Its effectiveness, accessibility, and safety
make it a suitable alternative to common additives.
Limitations & Challenges
The experiment was limited by lack of advanced microbial identification tools. Only short-
term effects were studied.
Safety Measures & Precautions
Handled all chemicals with gloves and lab coat. Sterilized all materials to avoid
contamination. Work was done under teacher supervision.
Real-World Applications
Used in winemaking, canned fruits, jams, and juices. Can be adopted in food industries
where acidic preservatives are preferred.
Future Scope & Advancements
Further research can analyze long-term effects and sensory impacts. Could include toxicity
studies and combination with other preservatives.
References & Bibliography
- NCERT Chemistry Textbook
- www.ncbi.nlm.nih.gov
- Journal of Food Science
- Chemistry of Food Additives, Springer
