Survival of E.coli during the manufacture of yogurt from cow's milk and soymilk blends at two storage temperatures

Date

6-2015

Degree

Bachelor of Science in Food Technology

Major Course

Major in Food Science

College

College of Agriculture and Food Science (CAFS)

Adviser/Committee Chair

Oliveros, Bryan Rey R.

Abstract

The study was conducted to be able to evaluate the survival rate of E. coli during the manufacture of yogurt made from cow's milk and soymilk blends at two storage temperatures (4 and 10°C). Sensory evaluation, physicochemical analyses (pH and TA), and microbiological analyses were done to evaluate the survival of E. coli in soy yogurt. Treatment B (60:40) milk: soymilk was inferred as the best treatment that can be used as a milk substitute in yogurt production through sensory evaluation. Moreover, there was no significant difference (p<0.05) in treatments of uninoculated samples. The general trend in decrease in pH and increase in TA was evident until the 10th day of storage while onset of deterioration was observed at the 18th and 20th day in LAB enumeration. There was no significant effect (p<0.05) in inoculation of E. coli in the physicochemical attributes of the yogurt. A decrease of about log 1.4 cfu/g of lactic acid bacteria (LAB) in both uninoculated yogurts stored at 4°C was seen while a decrease of about 1.5 cfu/g in treatment A, and 2.0 cfu/g drop in treatment B were observed. However, an evident increase in LAB counts was observed after the 4th day in both yogurt samples stored at 4 and 10°C. E. coli was observed to be reduced to <1g CFU/g at 6th day of storage (B), and 8th day if storage (A).

Language

English

Call Number

LG 993.5 2015 F61 /B66

Notes

status: in process

loc: UPLB Main Library Cataloging Section

Document Type

Thesis

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