Microbiological Evaluation of Vegetable Sprouts and Seeds

Area of Science:

• Food Microbiology
• Microbial Food Safety

Background:

• Sprouts are increasingly popular but can be vehicles for foodborne pathogens.
• Microbial contamination of sprout seeds and sprouts is a significant public health concern.

Purpose of the Study:

• To assess the microbiological quality of commercial sprout seeds and retail sprouts.
• To determine the impact of seed germination on microbial load.

Main Methods:

• Microbiological analyses were performed on commercial sprout seeds and retail sprouts.
• Aerobic plate counts (APC), confirmed coliforms, and fecal coliforms were quantified.
• Presence of Listeria, Salmonella, and coagulase-positive staphylococci was investigated.

Main Results:

• Commercial sprout seeds had APC ranging from <30x10^2 to 40x10^3/g and confirmed coliforms from 0 to >11x10^3/g.
• Fecal coliforms were detected in seeds (7.3-11x10^2/g); Listeria and Salmonella were absent.
• Pregerminating seeds in water increased APC by approximately one logarithm and elevated confirmed and fecal coliform levels.
• Retail sprouts exhibited high APC (3.6x10^3 to 3.7x10^9/g) with universal confirmed and fecal coliform presence.
• Coagulase-positive staphylococci were found in 24% of retail sprout samples.

Conclusions:

• Sprout seeds and retail sprouts can harbor significant microbial loads, including coliforms.
• Seed germination processes can enhance microbial contamination.
• Retail sprouts frequently exceed safe microbial limits, posing a potential risk to consumers.