Hurdle Technology
NOTES ON FOOD PRESERVATION & PACKAGING FOR MSc STUDENTS By Prof C S Purushothaman – Feb 2013
HURDLE TECHNOLOGY
The spoilage and poisoning of foods by micrnorgenisms is a problem that is not yet under adequate control, despite the range of preservation techniques available (e.g. freezing, blanching, pasteurizing and canning). In fact, the current Consumer demand for more natural and fresh-like foods, which urges food manufacturers to use only mild preservation techniques (e.g. refrigeration, modifed-atmosphere packaging and bio-conservation), should make this problem even greater. Thus, for the benefit of food manufacturers there is a strong need for new or improved mild preservation methods that allow for the production and fresh-like, but stable and safe foods. The concept of hurdle technology is not new but addresses this need in full. Hurdle technology (also called combined methods, combined processes, combination preservation, combination techniques or barrier technology) advocates the deliberate combination of existing and novel preservation techniques in order to establish a series of preservative factors (hurdles) that any microorganisms present should not be able to overcome. These hurdles may be temperature, water activity (a,), pH, redox potential, preservatives, and so on. It requites a certain amount of effort from a microfganism to overcome each hurdle. The 'higher" the hurdle, the greater the effort (i.e. the larger the number of orgenisms needed to overeome it). Some hurdles, like pasteurization, can be high for a large number of different types of microorganisms whereas others, like salt content, have a less strong effect or the effect is limited in the range of types of microorganisms it effects. The fact that a combination of preservative factors influences the microbial stability and safety of foods has been known for many centuries. Tbe concept is more or less unconsciously used in many traditional foods, especially in the developing
HURDLE TECHNOLOGY
The spoilage and poisoning of foods by micrnorgenisms is a problem that is not yet under adequate control, despite the range of preservation techniques available (e.g. freezing, blanching, pasteurizing and canning). In fact, the current Consumer demand for more natural and fresh-like foods, which urges food manufacturers to use only mild preservation techniques (e.g. refrigeration, modifed-atmosphere packaging and bio-conservation), should make this problem even greater. Thus, for the benefit of food manufacturers there is a strong need for new or improved mild preservation methods that allow for the production and fresh-like, but stable and safe foods. The concept of hurdle technology is not new but addresses this need in full. Hurdle technology (also called combined methods, combined processes, combination preservation, combination techniques or barrier technology) advocates the deliberate combination of existing and novel preservation techniques in order to establish a series of preservative factors (hurdles) that any microorganisms present should not be able to overcome. These hurdles may be temperature, water activity (a,), pH, redox potential, preservatives, and so on. It requites a certain amount of effort from a microfganism to overcome each hurdle. The 'higher" the hurdle, the greater the effort (i.e. the larger the number of orgenisms needed to overeome it). Some hurdles, like pasteurization, can be high for a large number of different types of microorganisms whereas others, like salt content, have a less strong effect or the effect is limited in the range of types of microorganisms it effects. The fact that a combination of preservative factors influences the microbial stability and safety of foods has been known for many centuries. Tbe concept is more or less unconsciously used in many traditional foods, especially in the developing