Summary of findings
Firstly, data was particularly drawn from the 10^-3 dilution set compared to the rest of the other sets due to it having the most number of fixed statistics in its dependent variable for each beverage. This makes it the most reasonable and accurate dilution set for this experiment, which supports the reason that data should be mainly derived from this set (10^-3 dilution set).
Also, we came to know more on the growth competency of L.casei on the various beverages tested. Based on the results, milk encourages L.casei growth best and coke deter L.casei growth worst among all the beverages. We are able to rank these beverages in ascending order of its effectiveness in growing L.casei , with cola being the least suitable, followed on by energy drink, continuing with sterile water, then tea, with LB Broth next, then coffee and finally, milk being the most suitable beverage.
1. Cola: L.casei bacteria colonies averaged at 0 CFU/ml for both tests. Additionally, based on previous or other dilution sets, had an overall average of 0 CFU/ml, which meant its results were consistent.
2. Energy drink: L.casei bacteria colonies averaged at 0 CFU/ml for both tests. Additionally, it averaged 10 CFU/ml for 10^0 dilution set, which meant its results were also consistent
3. Sterile water: L.casei bacteria colonies averaged at 0 CFU/ml for both tests. However, this was contrary to previous dilution sets where it averaged TMTC for 10^0 dilution set.
4. Tea: L.casei bacteria colonies averaged at 8 CFU/ml for both tests. In addition, it also had several middle range statistics for 10^0 dilution, 10^-2 dilution, and 10^-4 dilution sets with averages of TMTC, 127 CFU/ml, and 1 CFU/ml respectively.
5. LB Broth: L.casei bacteria colonies averaged at 239 CFU/ml for both tests. Moreover, it also had several proportionate statistics for 10^0 dilution, 10^-2 dilution, and 10^-4 dilution sets with averages of TMTC, 1491 CFU/ml, and 45 CFU/ml respectively.
6. Coffee: L.casei bacteria colonies averaged at 3185 CFU/ml for both tests. Besides, it had statistics that were almost in proportion, for 10^0 dilution, 10^-2 dilution, and 10^-4 dilution sets with averages of TMTC, 1720 CFU/ml, and 154 CFU/ml respectively.
7. Milk: L.casei bacteria colonies averaged at 3781 CFU/ml for both tests. Also, it had consistent results of proportion, for 10^0 dilution, 10^-2 dilution and 10^-4 dilution sets with averages of TMTC, TMTC, and 569 CFU/ml respectively.
After much discussion, we deduced that cola allowed zero L.casei growth due to the high contents of [caffeine] in it. Likewise, we believe that the energy drink also allowed low numbers of L.casei growth because of the presence of [caffeine] in it. On the other hand, our guess of why milk turned out to be the most effective beverage in encouraging the growth of L.casei is because milk contain the natural sugar, lactose, of which Lacti acid bacteria like L.casei feed on or ferment to convert these sugars into lactic acid. This allowed the growth of L.casei as the lactose in the milk provided food, or rather a substance required in the natural process of fermentation.
However, this project does not just stay in the lab, but is also capable of practical applications in the real world. From the results of this project, we are able to prove that certain beverages like milk are fit for consumption with probiotic drinks while some are not, like cola and energy drinks. Additionally, there is one more group where the effects of it on L.casei are very minimal and insignificant. Then, we are able to use this prove to use it practically.
First and foremost, we are able to give important, supported advice to probiotic drink manufacturers to state in their prescription which beverages to consume with or not to take with. This would, in a way, inform the consumers of these probiotic drinks to know how to take them. Ultimately, this would minimize complications caused by the effect of certain beverages on the probiotics in our gut flora.
In addition, we can convince governments to encourage companies manufacturing beverages to limit their ingredients to more probiotic-friendly ones. With this, the commonly consumed beverages will be more compatible with the probiotics in body, particularly Lactobacillus, which will eventually lead to the reduction of hazards towards human health.
Lastly, another example would be to raise awareness of this issue of the effect of common beverages on probiotics on the general public itself via public efforts like events or science fairs. This would educate the public on the selection of beverages at certain times and the frequency of it. With this efforts, more people would be aware of what happens when a certain beverage gets ingested, especially its interaction with probiotics in the stomach flora.
Areas for further study
There were many areas that we could have pursued our project on, if only for a longer time period given. Continuation of the project into areas of experimenting each individual beverage more in-depth on the reasons why they inhibit or aid the growth of L.casei (Example: moving down to a substance in the beverage that influences this effect). Also, carrying on of the project into retesting certain beverages with contradicting results on different sets if not all to ensure reliability and accuracy of results. On top of that, the expanding in the diversity of the independent variable (the type of beverages) could also be done. This would allow a larger diversity of beverages to be tested, which in turn, allows more data to be produced to be used eventually in practical application.
First, the continuation of the project into areas of experimenting each individual beverage more deeply on the reasons of them inhibiting or aiding the growth of L.casei simply refers to identifying a potential substance inside the beverage and testing it. By testing it, we are able to look for relationships of different beverages with the similar substance and their effects on the growth of L.casei. An example would be the cola set narrowed down to testing caffeine instead to confirm that caffeine was the root cause of the effect of L.casei not growing with the beverage cola.
Secondly, the carrying on of the project into retesting certain beverages with contradicting results on different sets if not all to ensure reliability and accuracy of results means to having retests for certain beverages with inconsistent results in different dilution sets. Still, this can result in the entire set being repeated. This retesting of certain beverages would produce more reliable results as it improves the consistency and figures out the problem the test is facing. An example would be having a retest for the set with sterile water because of its inconsistent results of having an average of TMTC for 10^0 dilution and an average of 0 for the remaining sets.
Thirdly, expanding the diversity of the independent variable (the type of beverages) relates to having more than just seven beverages used for the experiment. This meant that more types of beverages will be tested and increases the reach of the project, which covers more topics, bring in more benefits due to the increased potential of having more practical applications or use.