Details

Snapshot 1: strong synergism of two barriers

Snapshot 2: additive effect

Snapshot 3: mild antagonism

Snapshot 4: strong antagonism

Snapshot 5: single barrier at maximum intensity

Hurdle technology [1] refers to food preservation by the combined effects of barriers to microbial growth. The barriers can be heat treatment, cold storage, lowered water activity ), lowered pH, the presence of salt, and added natural and/or synthetic antimicrobial chemical agents. Traditionally, the combined effect has been represented as a series of "hurdles" of different heights spaced horizontally as in a track-and-field competition, which spoilage or pathogenic microorganisms fail to pass over. According to John Troller [2, 3], it is more revealing to stack the hurdles on top of each other to create a wall that can be insurmountable to the target microbe(s). This Demonstration shows the principle with three hypothetical barriers whose heights you can vary with sliders. You can also vary the combined heights multiplied by a factor, , (), with a slider. When the factors' effects are merely additive. When the factors are synergistic, and when they are antagonistic. Elimination of a factor can be done by setting its value to zero, the slider's minimum setting.

References

[1] L. Leister and G. W. Gould, Hurdle Technologies, New York: Kluwer Academic/Plenum Publishers, 2002. doi:10.1007/978-1-4615-0743-7.

[2] J. A. Troller, Personal communication, 1983.

[3] Y. Dai, L. A. McLandsborough, J. Weiss, and M. Peleg, "Concentration and Application Order Effects of Sodium Benzoate and Eugenol Mixtures on the Growth Inhibition of Saccharomyces cerevisiae and Zygosaccharomyces Bailii," Journal of Food Science, 75(7), 2010 pp. 482–488. doi:10.1111/j.1750-3841.2010.01772.x.