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Today, a huge range of alternatives of pre-prepared, refrigerated foods with a longer shelf-life (the period during which food maintains all its original characteristics of quality and safety) are available to consumers. Although they have been subjected to some type of treatment they maintain the fresh product characteristics, a goal that is achieved through the application of light preservation techniques such as refrigeration, moderate heating, packaging in modified atmosphere as well as the use of antimicrobial systems. The aim of this work was to identify new antimicrobial, biological agents with benefits to human health, which may be used for disinfecting salads and in the food industry. For this purpose, we used as biological material essential oils (EO) from different plants, known to contain terpenoids and bioactive phenolic compounds, and fermented cheese whey, mainly composed by lactic acid and bioactive polypeptides. Our results apoint out that fermented whey can be a viable and healthy alternative as an antibacterial agent and a source of bioactive peptides with high potential not only for the food industry, but also for medicine and nutraceutics.

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Isabel Santos worked as the head of the Microbiology Laboratory at INSA in Lisbon and is currently a professor of Food Safety and Microbiology. Her PhD in Food Engineering was concluded with praise and distinction and was granted the 1st prize of the FOOD&DT Award for Food Technology in 2011. She continues her research at ISA, Lisbon University.

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