Assessment of Microbial Contamination of Coins Collected from Local Market of Khed City, District Ratnagiri, Maharashtra

Sujit Nagare, Sneha Limbani, Shrushti Chalke, Raj Ambre, Vipul Sansare,

doi:10.5281/zenodo.14726139

Research Paper | Open Access
Volume 03 | Issue 01 | Article Id IJPS/250301181

Assessment of Microbial Contamination of Coins Collected from Local Market of Khed City, District Ratnagiri, Maharashtra
Sujit Nagare* Sneha Limbani Shrushti Chalke Raj Ambre Vipul Sansare
Dnyandeep College of Pharmacy, Boraj, Khed, Maharashtra, 415709, India

Abstract

Coins and currency play a vital role in the public and economic systems of societies. Coins serve as a widely accepted form of payment for goods and services. They make transactions efficient by providing a tangible means of exchange. Without coins and currency, trade would be cumbersome, relying on bartering or more complex trade systems. However, the exchange of coins carries a significant risk of microbial contamination due to the frequent handling and physical contact involved. The chances of microbial contamination during coin exchange are influenced by several factors, including the environments where coins are used, the types of microbes involved, and the hygiene practices of individuals involved in the transaction. Thus, present study has initiated with an aim to measure microbial contamination of coins collected from local market at Khed city.

Keywords

Coins currency, Microbial contamination, Local market, Khed city

Introduction

Coins serve as a widely accepted form of payment for goods and services. They make transactions efficient by providing a tangible means of exchange. Without coins and currency, trade would be cumbersome, relying on bartering or more complex trade systems. While coins are essential as a medium of exchange, their role in microbial transmission cannot be ignored. They can carry and spread harmful microorganisms, particularly in environments where proper hygiene is not observed. With so many individuals handling the same coins in public spaces, the likelihood of contamination increases. Microorganisms can be transferred from one person to another through direct skin-to-coin contact, as well as by touching contaminated surfaces (e.g., cash registers, counters, or vending machines)(1). Microorganisms tend to thrive in warmer and more humid environments. In high-humidity or crowded areas (like markets or public transport), coins are more likely to be contaminated with pathogens. Coins exchanged in buses, trains, or taxis can carry viruses and bacteria from one passenger to another. These public spaces have high foot traffic, contributing to a higher risk of microbial exposure. In crowded venues like stadiums or concert halls, coins are exchanged frequently, creating multiple opportunities for microbes to spread. Some metals (e.g., copper) have natural antimicrobial properties and may reduce the survival time of certain bacteria. However, other metals used in coinage, such as nickel or zinc, are less effective in limiting microbial growth (2). Thus, present study has started with an aim to collect coins from various shops at local market of Khed city and assess microbial contamination on the same. The study was conducted within area of curvature 10 kms of Khed city where coins of Indian currency were collected randomly from 20 shops. The collection of coins was done on 2^nd October 2024. Total of 40 currency coins consisting of 1 rupee (22 coins), 2 rupees (15 coins) and 5 rupees (3 coins) were collected in sterile zip lock bags. Collection was done by students randomly from vegetable vendors, grocery vendors, fish market vendors, barbers, bakery owners and bus conductors. To collect the coin currency, the shop keepers were requested to drop currency coins into a sterile zip lock bags, labelled and transferred to laboratory for assessment; coins were not touched by the author at any stage of collection (3).

Figure 1 Representative image of collected coins and collection procedure

The soft-agar overlay technique was used for assessment bioburden on the collected coins. Briefly, first layer of sterile nutrient agar was added to sterile petri plates, one coin was placed over the agar layer upon solidification of agar (4). Later on, second layer of sterile agar was placed over the coin at temperature 40-42⁰C. This has made a sandwich of the coins in the two layers of sterile nutrient agar medium as shown in figure 2. After solidification, plates were incubated overnight at 37⁰C. After prescribed incubation, plates were evaluated for the presence of microbial colonies. Colonies were counted on colony counter machine (5).

Figure 2 Soft agar overlay technique for assessment of microbial colonies over the coin.

The present study revealed the extent and the level of microbial contamination of coin currency which are widely use in local market. It was found that, microbial colonies are found on almost all coins. The microbial colonies are found to be more on coins collected from hotels, meat shop, fish shop and medical shop. This study was carried out to create awareness about microbial transmission through use of coins.

Table 1 Number of microbial colonies found on inoculation of coin in each plate

Types of shop	Shop I	Shop II
Types of shop	Number of microbial colonies
Fish Shop	03	03
Meat shop	07	02
Grocery Store	00	00
Jewellery shop	02	00
Salon	00	00
Cold Drink/Ice Cream	01	03
Cake shop	02	00
Sweet Mart	01	00
Hotels/Restaurant	08	09
Street Food Shop	00	00
Vegetables/Fruits	01	00
Garments	04	00
Hardware	04	01
Medical	05	00
Hospital/Clinic	00	00
Bus stand	00	00
Stationary Shop	02	00
Automobile Garage	01	00
Supermarket	05	01
Collage Campus	02	00

Figure 3 Graphical representation of microbial colonies on each coin.

REFERENCES

Pope TW, Ender PT, Woelk WK, Koroscil MA, Koroscil TM. Bacterial contamination of paper currency. South Med J. 2002 Dec;95(12):1408–10.
Sucilathangam G, Reventh AM, Velvizhi G, Revathy C. Assessment of Microbial Contamination of Paper Currency Notes in Circulation. Int J Curr Microbiol Appl Sci. 2016 Feb 15;5(2):735–41.
Analysis of Microbial Load on Money and Coin Currency handled at the Centennial College Tim Hortons and college bookstore. Available from: https://www.researchgate.net/publication/371695976
Mackenzie AMR, Rivera-Calderont RL. Agar Overlay Method to Measure Adherence of Staphylococcus epidermidis to Four Plastic Surfaces. Vol. 50, APPILIED AND ENVIRONMENTAL MICROBIOLOGY. 1985.
Hockett KL, Baltrus DA. Use of the soft-agar overlay technique to screen for bacterially produced inhibitory compounds. Journal of Visualized Experiments. 2017 Jan 14;2017(119)..