# Bacterial Diversity and Dominant Spoilage Microorganisms in Fresh-Cut Broccoli
## 3 Results
### Effects of spoilage microorganisms on the Quality of Broccoli  
Regardless of the cutting types, the diversity of spoilage bacteria isolated from broccoli was similar. In the present study, we collected more than ninety colonies of bacteria from broccoli and selected four major isolates based on colony phenotype grown on PCA medium. The phylogenetic trees of the four strains are shown in Figure 5 and their impacts are shown in Table 3. The results showed that each of the strains had different effects on the quality of the broccoli, _Pseudomonas_ spp. particularly. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Storage** & **Chlorophyll** & **Nitrite** & **MDA** & **Soluble Sugar** \\  & **Time (d)** & **(mg/g(Fw))** & **(mg/kg)** & **(nmol/g(Fw))** & **(mg/g(Fw))** \\ \hline  & 0 & 0.39 \(\pm\) 0.01 A & 0.31 \(\pm\) 0.03 BCD & 1.62 \(\pm\) 0.07 CD & 2.66 \(\pm\) 0.03 BCD \\ \hline \multirow{3}{*}{control} & 1 & 0.33 \(\pm\) 0.02 ab & 0.35 \(\pm\) 0.02 CA & 4.65 \(\pm\) 0.04 ab & 2.70 \(\pm\) 0.04 bB \\  & 2 & 0.29 \(\pm\) 0.00 AC & 0.11 \(\pm\) 0.02 CD & 7.39 \(\pm\) 0.22 CA & 2.83 \(\pm\) 0.01 dA \\  & 3 & 0.27 \(\pm\) 0.01 AC & 0.16 \(\pm\) 0.01 eC & 4.79 \(\pm\) 0.07 ab & 2.86 \(\pm\) 0.06 bA \\ \hline \multirow{3}{*}{_Pseudomonas_ spp.} & 1 & 0.19 \(\pm\) 0.01 dB & 1.61 \(\pm\) 0.09 nA & 3.85 \(\pm\) 0.15 bB & 3.17 \(\pm\) 0.02 aB \\  & 2 & 0.18 \(\pm\) 0.01 bB & 0.77 \(\pm\) 0.02 aB & 11.67 \(\pm\) 0.04 aA & 3.54 \(\pm\) 0.05 aA \\  & 3 & 0.13 \(\pm\) 0.01 dC & 0.66 \(\pm\) 0.00 aC & 3.20 \(\pm\) 0.15 bC & 2.94 \(\pm\) 0.05 bC \\ \hline \multirow{3}{*}{_Pseudomonas_ spp.} & 1 & 0.23 \(\pm\) 0.01 cB & 0.71 \(\pm\) 0.04 bA & 3.25 \(\pm\) 0.03 cB & 3.16 \(\pm\) 0.03 aB \\  & 2 & 0.17 \(\pm\) 0.01 bC & 0.23 \(\pm\) 0.04 bC & 8.72 \(\pm\) 0.03 bA & 3.17 \(\pm\) 0.02 bB \\  & 3 & 0.16 \(\pm\) 0.01 cC & 0.34 \(\pm\) 0.01 cB & 3.03 \(\pm\) 0.11 bC & 3.25 \(\pm\) 0.03 aA \\ \hline \multirow{3}{*}{_Actinebacter_ spp.} & 1 & 0.32 \(\pm\) 0.01 aB & 0.36 \(\pm\) 0.02 CA & 3.59 \(\pm\) 0.06 bB & 2.69 \(\pm\) 0.03 bB \\  & 2 & 0.27 \(\pm\) 0.02 cC & 0.12 \(\pm\) 0.01 cD & 7.23 \(\pm\) 0.02 cA & 2.85 \(\pm\) 0.04 dA \\ \cline{1-1}  & 3 & 0.24 \(\pm\) 0.00 bD & 0.24 \(\pm\) 0.02 dC & 3.24 \(\pm\) 0.15 bC & 2.90 \(\pm\) 0.05 bA \\ \hline \multirow{3}{*}{_Communons_ spp.} & 1 & 0.27 \(\pm\) 0.01 bB & 0.35 \(\pm\) 0.02 cB & 2.77 \(\pm\) 0.11 cB & 2.73 \(\pm\) 0.06 bB \\ \cline{1-1}  & 2 & 0.17 \(\pm\) 0.02 bC & 0.23 \(\pm\) 0.04 bC & 6.59 \(\pm\) 0.04 dA & 2.96 \(\pm\) 0.03 cA \\ \cline{1-1}  & 3 & 0.14 \(\pm\) 0.01 dD & 0.38 \(\pm\) 0.01 bA & 2.47 \(\pm\) 0.19 cC & 2.66 \(\pm\) 0.02 cB \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The influence of spoilage microorganisms on the chlorophyll, nitrite, MDA and soluble sugar content of fresh-cut broccoli during 72 h of storage at 20 \({}^{\circ}\)C. All data were recorded as the mean \(\pm\) standard errors (SE). Values with different letters were significantly different at \(p\)\(<\) 0.05. Lowercase letters represent significant differences among treatment factors; capital letters represent significant differences among storage durations. Figure 4: The culturable bacterial composition of fresh-cut broccoli at the phylum (**A**) and genus (**B**) levels. **Figure 5**. _Cont._Chlorophyll is an important indicator of plant vital signs in the photosynthesis of plant cells, which can absorb light energy to synthesize carbohydrates, carbon dioxide, and water. Thus, the change of chlorophyll content was considered to be an important factor affecting the quality of broccoli during the preservation. As shown in Table 3, the content of total chlorophyll in broccoli decreased during the storage. After 72 h, the total chlorophyll content in fresh-cut broccoli inoculated with _Pseudomonas_ sp. BRO-C11 and _Comomonas_ sp. BRO-C5 decreased by 51.9% and 48.1%, respectively, compared with the control. At the end of storage, the total chlorophyll content was decreased by 30.8-66.7% compared with the initial value, but _Acinetobacter_ sp.