| Autor: |
Garg, Ananya, Jana, Pranava, Rai, Soumya, Wu, Jeslyn |
| Předmět: |
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| Zdroj: |
National High School Journal of Science; Summer2020, p1-15, 15p |
| Abstrakt: |
Milk is a substance with high nutritional value and is highly prone to microbial contamination. Expiration dates on milk aim to predict a date signifying when the milk can no longer be safely consumed due to chances of contamination. This study aims to identify any possible coliforms that may develop in milk before and after the expiration date. By performing tests such as Methylene Blue Reduction Test (MBRT) and looking for growth on selective media for microbial activity, we determined the effectiveness of pasteurization on milk quality until expiration. Due to the high viability of coliform growth in milk, various tests such as acid and gas production and IMViC tests were performed to isolate and identify any strains of coliforms which can cause disease. We tested milk samples at 3 intervals: 5 days before expiration, on expiration, and 5 days after expiration. We found no microbial presence except in one of three samples after expiration. We used reference charts/tables along with picture references of different bacteria strains growing on agar to use visual observations to cross-reference and determine that we did not isolate E. coli. The results show that expired milk is unsafe and is prone to microbial contamination after the date of expiry. Due to the heat-shock processing methods commonly used by milk manufacturers, milk expiration dates are displayed as a precaution for consumers' well-being as the true-expiration date is often after the labeled date. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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