Microbiological Quality of Commercial Tofu

Area of Science:

• Food Science
• Microbiology
• Food Safety

Background:

• Tofu is a widely consumed soy product.
• Microbiological quality is essential for food safety and shelf-life.
• Limited data exists on the microbial load of commercial tofu at retail.

Purpose of the Study:

• To assess the microbiological quality of commercial tofu.
• To determine levels of various microbial groups in tofu.
• To evaluate the impact of storage conditions on microbial growth.

Main Methods:

• Developed a sampling method for accurate tofu microbial counts.
• Performed plate counts for total aerobic organisms, psychrotrophs, coliforms, sporeformers, yeasts, molds, and staphylococci.
• Analyzed 60 tofu samples from four brands and assessed microbial growth during simulated storage.

Main Results:

• 83% of tofu lots exceeded 10^6 CFU/g for total aerobic counts.
• 67% of lots had coliform counts over 10^3 CFU/g.
• Tofu stored until the pull date showed increased total and psychrotrophic counts.

Conclusions:

• Commercial tofu frequently exhibits high microbial loads, particularly coliforms.
• Processors must enhance sanitation and processing to reduce initial microbial contamination.
• Retailers need to ensure consistent, colder refrigeration to maintain tofu quality.