Shelf-life study of a vegetable-based juice prepared using a masticating juicer
Edgar, Karen (author)
Heacock, Helen (Advisor)
Keilbart, Ken (Advisor)
Lee, Melinda (Advisor)
British Columbia Institute of Technology School of Health Sciences (Degree granting institution)
Background Home juicing has seen a rise in popularity because it gives people an appetizing way to get their daily intake of fresh fruits and vegetables. The roles of proper refrigeration, pasteurization, and acidification are all important in regards to determining the shelf life of a freshly made juice. As the general public may not properly understand these implications, this could become a major concern for public health officials. Methods A vegetable-based juice, made with carrots, celery, apples and parsley was made using a masticating juicer. Two versions of the juice were made, one original and one acidified. The pH, total coliforms, and total bacterial levels were monitored in both versions of the juice over a fifteen-day period. Results Analyses were carried out with the two juice samples. The pH values of the two juices were significantly different (p = 0.0000). No statistically significant difference was found in either the total number of aerobic bacteria or coliforms in the acidified and original juices. The relationship between total bacterial count and pH in the both the acidified and neutral juices were statistically significant, r= 0.7659, p= 0.0098 and r=0.7334, p=0.0158, respectively. No statistically significant correlation was found between coliforms and pH. Conclusion Although it was expected that the acidified juice would have had a lower levels of bacterial growth, this research project failed to show this. The total bacterial levels in the acidified juice was greater than 106 CFU/g on Day 8 and the original juice was greater than 106 CFU/g on Day 10. Regardless of the pH, the safest and lowest bacterial levels will be right when the juice is made.
© Karen Edgar 2014. All rights reserved. No part of this work covered by the copyright heron may be reproduced or used in any form or by any means – graphics, electronic, or mechanical including photocopying, taping, or information storage and retrieval systems – without written permission of the author.
Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2014.