Purpose: The aim of this research is to investigate the diversity and abundance of the microbiome present in salad products.
Methods: Three commercial salad products (A, B, and C) were stored in the refrigerator (4°C) for 15 days. Samplings were on day 0, 5, 10, and 15. PCR-DGGE was used to evaluate the changes of the microbiome in three brands of salad. The Shannon index was calculated to measure microbial diversity. The populations of aerobic and anaerobic bacteria were enumerated by plating samples on trypticase soy agar (TSA) and anaerobic agar (AA).
Results: The Shannon indexes of microbial diversities were 2.234±0.069, 2.573±0.075, and 2.373±0.053 for brands (A, B, and C) initially. The Shannon index decreased from 2.311 to 1.976 for brand B, while the indexes remained the same for brands A and C from day zero to day 15. Total aerobic bacteria increased by 1.582, 1.790, and 1.630 log CFU/g from 8.048, 8.134, and 8.098 log CFU/g by day five for brands A, B, and C, then decreased to 8.050, 8.201, and 8.472 log CFU/g by day 15. The populations of anaerobic bacteria in the three brands decrease by 0.997, 0.685, and 0.347 log CFU/g during the 15 days of storage. Salad from brand B decayed more than the other two brands.
Significance: Different microbial diversity and abundance were found among the three brands. This observation highlights the importance of further evaluating the microbiome present in salad products.