Purpose: A rapid detection method was developed to significantly shorten time to detection of contaminants. The compatibility of different matrix and performances of the rapid system were challenged to detect critical spoilage contaminants in specific food and beverage samples.
Methods: The EZ-Fluo Rapid Detection System method, based on universal fluorescent staining of microorganisms, is composed of sample filtration on membrane and incubation on traditional culture medium. After a short and validated incubation time, membranes are transferred onto a cellulose pad soaked with staining solution allowing enumeration of fluorescent micro-colonies. After staining, membranes can be re-incubated onto medium to continue growth allowing species identification.
Results: Filterability, fluorescent background and potential antimicrobial activity of two products were previously checked showing full method compatibility. Aspergillus brasiliensis and Candida albicans are detected in coconut powder after 24 hours of incubation on Sabouraud Dextrose Agar at 25°C instead of 5 days. In the same way, the detection time of Alicyclobacilli in energy drink is 20 hours on Potato Dextrose Agar instead of 3 days. The slope of the linear regression of three levels of Alicyclobacilli contamination is close to 1. Using a significance level of 0.1, the Anderson-Darling normality test indicates that the microbial counts follow a normal distribution. Regarding fluorescent enumeration, the P-values from Student test (P ≥ 0.05) versus reference method are 0.674, 0.188, and 0.698, respectively, for the low, medium and high level of contamination demonstrating the equivalence between both methods.
Significance: The alternative method divides times-to-result by three to five compared to control method and gives earlier detection of contaminants and would significantly improve process and product quality.