Prevalensi Bakteri Coliform pada Susu Kedelai yang Dibeli dari Penjual Lokal di Surabaya, Indonesia The Prevalence of Coliform Bacteria in Soybean Milk Purchased from Local Sellers in Surabaya, Indonesia

Firdaus et al. MKH (2020). 137-146 DOI: 10.20473/mkh.v31i3.2020.137-146 2020. Firdaus et al. Open access under CC BY – SA license, doi: 10.20473/mkh.v31i2.2020.85-96 Received: 16-08-2020, Accepted: 14-092020, Published online: 29-09-2020 Available at https://e-journal.unair.ac.id/MKH/index 138 Soymilk was processed from extracted soy. Soymilk is well known among people who were intolerance with a milk product. This study aim is to verify hygienic and safety of the soymilk which was prepared by local sellers. The microbial presence in 30 soymilk products were determined using the streak plate technique with MacConkey agar medium. Bacterial identification was confirmed with a biochemical assay using triple sugar iron test, indol test, citrate test, methyl red test, voges proskauer test, motility test. Among 30 samples, 40% of samples were contaminated with coliform bacteria. Among those contaminated with coliform, 3% contaminated with Escherichia coli and 40% contaminated with Enterobacter. The implications from our study is that the quality of soymilk product from local sellers need to be monitored to avoid transmission of infections to the buyer. Thus, counselling about hygienic and safety of food production will be necessary to ensure soymilk products free of pathogenic microorganisms in the future.


INTRODUCTION
Soy is a type of legume indigenous to eastern Asia. Soy itself becomes an essential part of Asian diets. There are many kind of soy product including soy flour, soy protein, tofu and soymilk.
Soymilk is suitable for consumption since it has high nutrition and it is considered as substitutions for cow`s milk, especially for that lactoseintolerant population (Adeleke, 2000).
Soymilk mainly is a high source of protein, polyunsaturated fatty acids, carbohydrates and dietary fibers (Brouns, 2002). Soymilk naturally contains isoflavones, that help lowdensity lipoprotein (LDL) cholesterol and thus will help reduce Cardiovascular Disease risk (Ramdath, 2017;Ofoefule, 2002). Other studies also reported its potential of isoflavones to protect against prostate cancer, breast cancer, uterine cancer, testicular cancer and other-hormone dependent cancers also osteoporosis (Patisaul, 2010 Acid/Acid reaction in butt and slant part of the media. If H2S is produced, the black color of ferrous sulfide will also be seen (Cain, 2013).

Motility Test
One that produce acetoin as end product will turn red after addition of alpha napthol 5% and potassium hydroxide 40% (Cain, 2013).

Indole Test
One loop of colonies from NAS were then inoculated in pepton water 1%.

Positive result when indole reacts with
Kovac's reagent, it will be developed in the surface of media. Organisms can break down the amino acid tryptophan to indole (Cain, 2013).
Enterobacter and Escherichia are included in coliform bacteria groups.
Coliform is a group of bacteria that is used as an incicator of fecal pollution and poor sanitation condition against water, food, milk, dairy products. The presence of coliform bacteria in food or beverage indicates the possibility of enteropathogenic miccroorganisms that are harmful to health (Irianto, 2013 (Seidler, 1975).
Contamination found in soymilk product can be caused by contamination during processing, or packaging (Paramasatiari, 2018). Soymilk were process in several step, after soybean was drained then added with fresh water and boiled for 30 minutes. Soybean then was grounded with grinding made from metal or stone until pulp was formed.
Boiling water was added to pulp then filtered with gauzed to obtain raw soymilk. Sugar and artificial flavor enhancer were then added to enhance the taste of soymilk (Koswara, 2009).
Several source for contamination can be detected from this whole processing alone such as tools for grinding, container for soybean storage after grinding process and after filtering raw soymilk. Another source for contamination could be detected from contaminated raw materials, lack of good manufacturing practice (Liamngee, 2013) and coming from packaging process. Our study showed that monitoring the quality of soymilk produced by street vendors to ensure the high-quality soymilk and prevent infection from pathogenic bacteria.

CONCLUSIONS
Our study showed that there is coliform contamination found in soymilk sold by street vendors. Coliform found were E.
coli and Enterobacter. This study urge that drinks sold by street vendors should be monitored to ensure safety and prevent infection from pathogenic bacteria.