3.4.4. Color Measurement

In Table 4, the lightness L\* color parameter for shreds of mid-tone, i.e., median green, can be seen. These results are too scattered to be able to differentiate between sanitizing treatments. The same was observed for the other color coordinates a\* and b\*. Although 30 shots were taken for each measurement and standard deviations are not high, the chances of taking shreds from different color groups are high and conclusive results cannot be drawn from these experiments. Nevertheless, it can be said that color was not dramatically affected by all treatments.


**Table 4.** Lightness (L\*) color parameter of the lettuce after sanitizer treatments, over 10 days in cold storage. Results represent the average of at least three replicate experiments (n = 3) ± SD.

## 3.4.5. Sensory Evaluation

From the sensory evaluation, one can see the resulting spider diagrams for chlorine and whey treatments in Figures 5a and 5b, respectively. Therefore, from the spider diagrams, one can see that all the attributes were highly scored, with all above the midpoint 5, over the 10 days of cold storage.

To compare the two treatments, overall acceptability was chosen to represent the sensory results, and in Figure 6 it can be seen that there are two major plateaus. The first showed top scores until day 5, and the second with scores around 6 from 7 to the 10th day of cold storage, probably related to the scores obtained for off-odors and flavor. From these results, no differences can be seen for the two treatments, with whey or with chlorine.

**Figure 5.** Sensory scores of the lettuce treated with chlorine solution (**a**) and Fermented whey (**b**) over 10 days in cold storage. Results represent the average of at least three replicate experiments (n = 3) ± SD.

**Figure 6.** Overall acceptability of the lettuce treated with fermented whey and chlorine over 10 days in cold storage. Results represent the average of at least three replicate experiments (n = 3) ± SD.


Enumeration of AM (aerobic microorganisms at 30 ◦C) is an indicator of quality and gives an estimate of total viable populations, both endogenous and contaminant microbiota, since microorganisms are inevitably introduced during manipulations [48]. However, in general, the initial contamination of vegetables reflects the microbiota environment in which they were grown [49,50]. Before treatment (day 0), the initial AM was 6.10 log cfu·g−1. Other works have found similar results in whole vegetables [28,51,52]. As can be observed in Figure 7a, AM counts sharply decreased after all treatments (*p* < 0.05). Throughout the storage, samples treated with whey always presented a significantly lower AM count (*p* < 0.001) when compared to water and chlorine, independent of time (*p* < 0.001). This is a strong indication of the effectiveness of fermented whey as an alternative disinfectant.

**Figure 7.** *Cont*.

**Figure 7.** Packed shredded lettuce: effect of sanitation on shredded lettuce Aerobic Microorganisms (**a**), Psychotropic Microorganisms (**b**), and Lactic Acid Bacteria (**c**) over 10 days in cold storage. Results represent the average of at least three replicate experiments (n = 3) ± SD.

#### 2. Psychrotrophic Microorganisms

Similarly to AM, psychrotrophic microorganisms (PM) counts were significantly reduced (*p* < 0.05) in all treatments at day 1 (Figure 7b). Also, the highest count reduction (*p* < 0.001) to 2.20 log cfu·g−<sup>1</sup> occurred in samples treated with whey. With chlorine, the count reduction found was 1.13 log cfu·g<sup>−</sup>1. In the case of the PM, both for the lettuce treated with whey as well as with chlorine, after 5 days in cold storage, there were no significant differences between both treatments in respect to these counts.
