Performance comparison of the BioSys optical assay and the violet red bile agar method for detecting coliforms in food products

Validation of the Soleris® Coliform Method for Detection of Coliform Bacteria in Dried Cannabis Flower: AOAC Performance Tested MethodSM 010302

Background

The Soleris® Coliform Vial is a growth-based, automated method for detection of coliform bacteria in foods and other consumer products such as nutraceuticals and cosmetics. The method was granted AOAC Performance Tested MethodSM certification for select foods after successful completion of a validation study.

Objective

The objective of the current study was to validate the Soleris coliform method for use with dried cannabis flower (>0.3% delta 9-tetrahydrocannabinol).

Methods

A comparative matrix study was performed in which naturally contaminated dried cannabis flower was tested with the Soleris coliform method and with the U.S. Food and Drug Administration Bacteriological Analytical Manual solid medium method. Multiple lots of dried cannabis flower were obtained, pre-screened for coliforms, and blended to produce test materials at four different contamination levels ranging from 4.5 to 1600 CFU/g. Each material was tested at three different Soleris detection threshold levels determined by the dilution used to inoculate the Soleris vials. Probability of detection analysis was performed to determine if differences in the number of positive results obtained with the two methods were significant.

Results

For all four dried cannabis flower materials, at all three Soleris test thresholds, there were no significant differences in the number of positive results obtained with the Soleris and cultural plating methods as determined by probability of detection analysis at P < 0.05.

Conclusion

The Soleris coliform test is an accurate method for detection of coliform bacteria in dried cannabis flower.

Highlights

The Soleris coliform method provides cannabis industry QC personnel with an effective method for analysis of dried cannabis flower and produces results in 18–24 h.

Soleris®Enterobacteriaceae for the Detection of Enterobacteriaceae in Select Foods: AOAC Performance Tested MethodSM 121901

Background

Soleris^®Enterobacteriaceae is a growth-based, automated method for detection of Enterobacteriaceae in food.

Objective

A study was conducted to validate the Soleris method for detection of Enterobacteriaceae in select foods (pasteurized milk, yogurt, mozzarella cheese, ice cream, dried milk, pasteurized liquid egg, frozen cooked chicken, deli ham, lettuce, and dry dog food) at a threshold of ≥ 10 CFU/g of product.

Methods

Inclusivity and exclusivity of the Soleris method were assessed by testing 55 and 38 target and non-target bacterial strains, respectively. Matrix testing was performed with one naturally contaminated and nine inoculated foods. Efficacy of the Soleris method was compared to that of the ISO 21528-2:2017 direct plating reference method using probability of detection analysis. Independent laboratory testing was conducted to verify method performance in two matrixes (yogurt and deli ham). Method robustness, stability, and lot-to-lot consistency of the Soleris reagents were also assessed.

Results

Inclusivity of the Soleris test was 91% and exclusivity was 100%. In matrix testing, there were no significant differences in the number of positive results obtained with the Soleris and reference methods for any of the matrixes examined. Overall, of 370 test portions, there were 176 positive results by the Soleris method and 177 positive results by the reference procedure.

Conclusions

Soleris Enterobacteriaceae is an effective method for detection of Enterobacteriaceae in the foods evaluated, with performance equivalent to that of the ISO 21528-2:2017 reference method.

Highlights

The Soleris method offers the advantages of labor savings and results within 18 h.