Dehydrated foods: Are they microbiologically safe?

Area of Science:

• Food Microbiology
• Food Safety Science
• Microbial Pathogenesis

Background:

• Dried foods have low water activity (0.03–0.7), often leading to a misconception of inherent safety from foodborne pathogens.
• Numerous foodborne illnesses have been linked to dried foods contaminated with pathogenic bacteria such as Salmonella spp., Cronobacter spp., Staphylococcus spp., and E. coli.

Purpose of the Study:

• To systematically review the scientific literature on the impact of drying and dehydration processes on the survival of pathogenic microorganisms.
• To specifically focus on the survival of Salmonella spp. in dried foods.
• To synthesize existing research on the effects of drying on microbial load in various dried food products, including vegetables, meat, fish, spices, mushrooms, and powdered foods.

Main Methods:

• Systematic literature review of studies investigating the effect of drying/dehydration on pathogenic microorganisms.
• Literature synthesis focusing on microbial survival in diverse dried food matrices (vegetables, meat, fish, spices, mushroom, powdered foods).

Main Results:

• Drying processes do not eliminate pathogenic microorganisms, and survival rates vary depending on the specific pathogen and food matrix.
• Pathogenic bacteria, including Salmonella spp., can survive dehydration and pose a significant risk in dried foods.
• Contaminated dried foods have been implicated in numerous outbreaks of foodborne illness.

Conclusions:

• Dried foods are not inherently microbiologically safe.
• Additional control measures or hurdles beyond the drying process are essential to ensure the microbial safety of dried food products.
• Further research is needed to develop and validate effective hurdle technologies for pathogen control in dried foods.