Too low pH of a food may impair taste of a food. Excessive Low temperature treatment may reduce food quality by destroying food surface (chilling injury) or due to release of enzymes by dead microbes. Severe heat treatments can impair the organoleptic properties and nutritional value of foods. The microorganisms present (‘at the start’) in a food should not be able to overcome (‘leap over’) the hurdles present during the storage of a product otherwise the food will spoil or even cause food poisoning. ![]() ![]() For each stable and safe food a certain set of hurdles is inherent, which differs in quality and intensity depending on the particular product, but in any case the hurdles must keep the ‘normal’ population of microorganisms in this food under control. By this adjustment, hurdles in foods can be kept in the optimal range, considering safety as well as quality, and thus the total quality of a food. If the intensity of a particular hurdles in a food is too small it should be strengthened, if it is detrimental to the food quality it should be lowered. Another example is the pH of fermented sausage which should be low enough to inhibit pathogenic bacteria, but not so low as to impair taste. For instance, chilling to an unsuitable low temperature is detrimental to some foods of plant origin (‘chilling injury’), whereas moderate chilling will be beneficial for their shelf life. The same hurdles could have a positive or a negative effect on foods, depending on its intensity. ![]() Some hurdles (e.g., Millard reaction products) will influence the safety and the quality of foods, because they have antimicrobial properties and at the same time improve the flavour of the products. However, more than 60 potential hurdles for foods, which improve the stability and/or quality of the products, have been already described, and the list of possible hurdles for food preservation is by no means complete. The most important hurdles generally used in food preservation are temperature (high or low), water activity ( a w), acidity (pH), redox potential (Eh), preservatives (e.g., nitrite, sorbate, sulfite ), and competitive microorganisms (e.g., lactic acid bacteria ).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |