1st Edition

Sensory Shelf Life Estimation of Food Products

By Guillermo Hough Copyright 2010
    264 Pages 63 B/W Illustrations
    by CRC Press

    Complying with food regulations and, more importantly, quality standards, requires practical and reliable methods to estimate a product’s shelf life. Emphasizing the importance of the consumer’s perception of when food has reached the end of its shelf life, Sensory Shelf Life Estimation of Food Products provides a tool for adequately predicting sensory shelf life (SSL).

    The book delineates the basics of sensory analysis and how it applies to shelf-life studies and includes discussions of experimental design aspects, survival analysis methodology, and its extensions. It provides detailed instructions and software functions for performing SSL estimations, accompanied by data sets and the R Statistical Package functions that are available for download. The author presents the cut-off point methodology used to estimate SSL when the survival analysis methods get complicated. He includes a chapter on accelerated storage covering kinetics, calculations of prediction confidence intervals and potential pitfalls. He also examines extensions of survival analysis statistics to other areas of food quality such as optimum concentration of ingredients and optimum cooking temperatures.

    Microbiologically stable foods, such as biscuits or mayonnaise, will have their shelf-life defined by the changes in their sensory properties. Many fresh foods, such as yogurt or pasta, after relatively prolonged storage may be microbiologically safe to eat but rejected due to changes in their sensory properties. Shelf life in most food products is determined by sensory issues instead of microbiological or chemical concerns. This book offers key techniques for experimental design, storage, consumer testing procedures, and calculations. It includes methods for accelerated storage experiments, thoroughly explains statistical data treatment, and includes practical examples.

    Introduction
    Sensory Shelf Life Definition
    Labeling Regulations
    Shelf Life of Foods Is Sensory Shelf Life
    Importance of the Consumer in Defining Food Quality
    Books on Shelf Life of Foods
    References

    Principles of Sensory Evaluation
    Introduction
    Definition of Sensory Evaluation
    Sensory Analysis: Trained Panels versus Experts
    General Requirements and Conditions for Sensory Tests
    Physiological Factors
    Psychological Factors
    Sensory Evaluation Methods
    References

    Design of Sensory Shelf-Life Experiments
    Initial Considerations
    Approximations of Shelf-Life Values
    References

    Survival Analysis Applied to Sensory Shelf Life
    What is Survival Analysis?
    Censoring
    Survival and Failure Functions
    Shelf Life Centered on the Product or on Its Interaction with the Consumer?
    Experimental Data Used to Illustrate the Methodology
    Censoring in Shelf-Life Data
    Model to Estimate the Rejection Function
    Calculations Using the R Statistical Package
    Interpretation of Shelf-Life Calculations
    An Additional Example
    Should Consumers be Informed?
    Is There a Way to Deal with Totally New Products?
    References

    Survival Analysis Continued: Number of Consumers, Current Status Data, and Covariates
    Number of Consumers
    Current Status Data
    Introducing Covariates in the Model
    References

    Cut-Off Point Methodology
    When is the Survival Statistics Methodology Difficult to Apply?
    Basics of the Cut-Off Point Methodology
    Approaches in Establishing a COP
    Methodology to Measure the COP
    Instrumental Cut-Off Points
    Caveats for Using COP Methodology
    References

    Accelerated Storage
    Introduction
    Arrhenius Equation and Activation Energy
    The Use of Q10
    Survival Analysis Accelerated Storage Model
    Potential Pitfalls of Accelerated Shelf-Life Testing
    Conclusion on Accelerated Testing
    References

    Other Applications of Survival Analysis in Food Quality
    Consumer Tolerance Limits to a Sensory Defect
    Optimum Concentration of Ingredients in Food Products
    Optimum Salt Level in French Bread
    Internal Cooking Temperature of Beef
    Optimum Ripening Times of Fruits
    References
    Index

    Biography

    A research scientist with the Commission de Ivestigaciones Cientificas, Guillermo Hough is a renowned academic in sensory/consumer sciences. Dr. Hough conducts his research in the area of sensory science and has become an expert in the field of sensory shelf life, having published 20 refereed articles on this theme. A dynamic speaker at international conferences and symposiums, he also lead the collaborative Ibero-American project (CYTED program), which stated the basics for the estimation and modelization of sensory shelf life. His course on sensory science and shelf life has been very popular in Argentina, Chile, Colombia, Italy, Mexico, New York and Paris. His group is in close contact with local and regional food companies, performing a wide range of sensory tests and panel testing. Dr. Hough works at the Instituto Superior Experimental de Tecnologia Alimentaria in the small town of Nueve de Julio, Provincia de Buenos Aires, Argentina.