Quantifying the spoilage and shelf-life of yoghurt with fruits

• Published in: Food microbiology Vol. 28; no. 3; pp. 611 - 616
• Main Authors: Mataragas, M., Dimitriou, V., Skandamis, P.N., Drosinos, E.H.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2011; Elsevier
• Subjects: Biological and medical sciences; Colony Count, Microbial; Food Contamination - analysis; Food industries; Food Microbiology; Food Preservation - methods; Food Preservation - standards; Fruit - microbiology; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Kinetics; Lactobacillus - growth & development; Modelling; Models, Biological; Predictive microbiology; Predictive Value of Tests; Shelf-life; Spoilage; Temperature; Yeasts - growth & development; Yoghurt with fruits; Yogurt - microbiology; Shelf-life; Modelling; Spoilage; Yoghurt with fruits; Predictive microbiology; Fruit; Dairy product; Food preservation; Shelf life; Yogurt
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2010.11.009

The aim of the present study was to develop a predictive model to quantify the spoilage of yoghurt with fruits. Product samples were stored at various temperatures (5–20 °C). Samples were subjected to microbiological (total viable counts, lactic acid bacteria-LAB, yeasts and moulds) and physico-chemical analysis (pH, titratable acidity and sugars). LAB was the dominant micro-flora. Yeasts population increased at all temperatures but a delay was observed during the first days of storage. Titratable acidity and pH remained almost constant at low temperatures (5 and 10 °C). However, at higher temperatures (>10 °C), an increase in titratable acidity and reduction in pH was observed. Sugar concentration (fructose, lactose and glucose) decreased during storage. A mathematical model was developed for shelf-life determination of the product. It was successfully validated at a temperature (17 °C) not used during model development. The results showed that shelf-life of this product could not be established based only on microbiological data and use of other parameters such as sensory or/and physico-chemical analysis is required. Shelf-life determination by spoilage tests is time-consuming and the need for new rapid techniques has been raised. The developed model could help dairy industries to establish shelf-life predictions on yoghurt with fruits stored under constant temperature conditions. ► Practical use by food industry of kinetic growth models which determine food shelf-life. ► Predictive model able of predicting yogurt shelf-life under constant temperature conditions. ► Information on shelf-life of specific dairy products category. ► Useful and practical tool for quality monitoring by dairy industry. ► Assistant in predicting storage life of yogurts with fruits under concrete business conditions.