Evaluation of the microbiological stability of whole-wheat sandwich bread by the use of natamycin

Abstract

In recent years there is a growing interest in consume natural food, that is, that they be minimally processed. Bioconservation satisfies these requirements since it take advantages of the capacity of microorganisms recognized as safe (GRAS) and their metabolites to inhibit the development of altering microorganisms or pathogens in food. In the bakery sector, the main drawback is the preservation of bread after baking, since the composition and storage temperature are very prone to be attacked by fungi. The purpose of the present investigation was to evaluate the microbiological stability of whole-wheat sandwich bread by spraying natamycin solutions with different concentrations of alcohol on the bread surface at 65°C and 30°C. The study involved microbiological analysis of molds and yeasts, determination of humidity and a sensory evaluation, by means of a triangular test with 24 semi-trained judges. Were followed the methodologies described in the AOAC and ISO methods. The analysis of humidity and the count of fungi and yeasts show that there are no significant differences (P <0.05) between the treatments. When it comes to the sensory analysis, it is evident that there are no significant differences in taste. These results show that the whole-wheat sandwich bread maintains its microbiological stability during the 18 days of study, being the use of the bioconservant a response for the consumers that continually look for fresher products and less amount of chemical additives.