Dry-inoculation methods for low-moisture foods

Abstract Background The knowledge of the thermal resistance of target pathogens in food matrices is a prerequisite for the design of effective control treatments. It is also desirable, or even necessary, to validate the treatments using appropriate surrogates for the target pathogens. To obtain the thermal death kinetic information for both the target pathogens and their surrogates or validate the effect of new thermal treatments using surrogates, bacteria of interests (pathogen or surrogate) must be introduced to the food matrices at an adequate concentration to obtain survivor curves. A major challenge for the inoculation of the bacteria in low-moisture foods (LMFs) is that the inoculation could result in changes to the physical characteristics of the food matrices. For example, alteration of the microstructures and particular size could lead to different moisture absorption and desorption behaviors of treated foods in thermal treatments. Scope and approach The safety of LMFs is an emerging concern in the food industry. Extensive research only took place over the past ten years, and dry-inoculation has risen as a promising tool for developing efficient treatments to control pathogens in LMFs. This paper provides a general review of the methodologies for LMFs inoculation. It summarizes the recently published work in the developments of dry-inoculation methods and compares the advantages and limitations of different LMFs inoculation methods. Key findings and conclusions Dry-inoculation is a more suitable approach for LMFs inoculation, which offers an attractive alternative to wet-inoculation. Dry-inoculation methods require a short preparation time, and the inoculum has a long shelf-life, minimal influence on the physio-chemical properties of the food matrices, and is easier to transport.