Assessment of survival of food-borne microorganisms in the food chain by fluorescence ratio imaging microscopy

Traditionally, many data on food-borne microorganisms are obtained as an average of a whole population, under the assumption that the individual cells are clonal and therefore identical. However, it is now acknowledged that there may be a large heterogeneity within an isogenic population, and consequently new methods focus on the individual cells. This mini-review will give an overview of the response of food-borne microorganisms; i.e. pathogenic bacteria, lactic acid bacteria, and yeasts, at a single-cell level to various food-related stress conditions, comprising acid-, disinfection-, salt- and sugar- and bacteriocin stress, as assessed by Fluorescence Ratio Imaging Microscopy.