Date of Award

Summer 8-2021

Document Type


Degree Name

Master of Science (MS)


Food Science

First Advisor

Rosalee Hellberg

Second Advisor

Anuradha Prakash

Third Advisor

Lilian Were


Plant-based meat alternatives are gaining popularity as the number of market options increases. However, the recent appearance of these products on the market post-dates the validation of the current approach for isolating Salmonella from meat analogs. Therefore, the objective of this study was to compare the efficacy of the currently used Bacteriological Analytical Manual (BAM) pre-enrichment broth (lactose broth) with two additional broths (universal pre-enrichment broth and buffered peptone water) for the detection of Salmonella in five plant-based burger products. Each burger product was spiked with a Salmonella serotype (S. Enteritidis or S. Agona) that has previously been linked to one or more of the protein sources in the product. The U.S. Food and Drug Administration (FDA) Matrix Extension Verification Procedure section 5.1.1 was followed for the verification of each broth. Seven replicates of each of the five selected plant-protein burgers were spot-inoculated with 30 or less colony-forming units (CFU) of Salmonella enterica per 25 g of product and enriched in each broth. An additional seven non-inoculated replicates were tested with all broths. Pathogen recovery was evaluated using the methods described in BAM and Salmonella was confirmed with real-time PCR, using two DNA templates per sample. Comparison of the number of positive real-time PCR detections for Salmonella across all three broths and five brands indicated no significant difference (p-value > 0.05) between the effectiveness of each broth. The greatest level of detection was found with LB, in which 95.71% of DNA templates tested positive for Salmonella, followed by BPW and UP broth, which each had an 88.57% detection rate. When the broths were compared for effectiveness in each product separately, LB showed a significantly greater percentage of positive detections (92.86%) in Beyond MeatTM samples compared to UP (50%). However, none of the other products showed significant differences in detection among the three broths. In conclusion, the findings demonstrate that LB, the current BAM pre-enrichment broth, is an effective pre-enrichment for the detection of Salmonella in meat analogs formulated with various plant-proteins.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.



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