Microbiological Quality and Safety of Energy Drink Available in the Local Markets in Saudi Arabia

Keywords

Energy drink; Microbiological quality; energy drink safety; Bacterial contamination.

Introduction

The global market for energy drink has gained momentum in the past decade, and demand is increasing every year. Likewise, there is an increased awareness of the importance of energy drink safety. Each year new energy drinks come on the market in Saudi Arabia [1,2].However, the Saudi Council of Ministers has decided to ban energy drink advertising altogether. This ban also applies to the distribution of free energy drinks to consumers of all age groups and prohibits the sale of energy drinks in restaurants and canteens in government facilities, education and health facilities, halls of government and private sports clubs. A committed council resolution of factory owners and importers of energy drinks has warned of the harmful effects of energy drinks [3,4]. As the global market for energy drinks approaches nearly $15 trillion, the general consumption of energy drinks has increased accordingly, particularly among college students. The consumption rates among this demographic are increasing because of the concentration enhancement and fatigue-relieving effects of energy drinks [5], yet there is relatively little information regarding the safety and quality of these products. In addition, information on the use of energy drinks among students is vague and misleading. In the quest to be the strongest and fastest, many students consume unproven, potentially harmful, or even banned energy drinks. Popular energy drinks such as Red Bull, Power Horse, Bison, Bugzy, Code Red, Boom Boom, Shark, Double Horse, Blu Day, Black, and AMP were used in this study [6,7,8]. Caffeine is no longer banned by the World Anti-Doping Agency. Nevertheless, one should only use caffeine with the advice of a sports scientist or sports dietitian and individual responses to caffeine should be considered. Red Bull energy drink is a popular carbonated taurine drink with caffeine that claims to vitalize the body and mind. Red Bull is designed especially for moments of increased physical and mental stress and improves endurance, alertness, concentration, and reaction speed. The effectiveness of Red Bull energy drink is supported by quite a bit of scientific research and endorsed by recognized sports professionals [9,10].The ergogenic effect of caffeine in endurance exercise performance is well established. Two important key factors are: microbiological quality and safety of commercial energy drinks available in the local stores.

Saudi Arabia

Cities of Saudi Arabia including Riyadh are very hot and arid reaching an average temperature as high as 36°C. Temperature, oxygen, and moisture content of the storage area are the most important factors that influence the type of microbial growth and spoilage. There are not well established and regulated criteria for the storage of food products including energy drinks in Saudi Arabian markets. As a result of this, even imported products such as energy drinks have been shown to be a potential risk factor for the development of microbial hazards. In addition, there is very limited published information regarding the quality and safety of these products in Saudi Arabian markets [11]. Therefore, in this study we tested the microbiological quality of these drinks to ensure that the products are safe.

Materials and methods

Samplings

Twenty different commercial energy drinks were collected from local stores in Riyadh, Saudi Arabia. The samples were collected based on the protocol described earlier by Aljaloud et al. [11]. The numbers of samples were based on the availability of drinks in a particular district of Riyadh. These products were randomly labeled with different number (three digest for day of month and time (example 110 means first day of the month 10 am). All products were picked in duplicates from each store and then shipped to Food Microbiology Laboratory at North Carolina Agricultural & Technical State University, Greensboro, NC, for microbial quality and product safety analysis.

Microbiological and Safety Quality Test

From each commercial sample, 25 ml of drinks were added in 100 ml sterilized Brain Heart Infusion (BHI) broth and mixed thoroughly. Samples were then incubated at 37°C for 4 h to allow for microbial cell recovery if present. One milliliter from each sample was then withdrawn and diluted with 0.1% peptone water. The appropriate dilutions were plated onto duplicate selective agar medium. To obtain the total bacterial count, samples were plated on BHI agar. To test for coliform and E. coli, samples were plated on Violet Red Glucose Bile agar (VRGBA) and MacConky agar, respectively. Similarly, samples were plated on Xylose lysine deoxycholate (XLD) agar for Salmonella, and Baird-Parkeragar (BPAB) for Staphylococcus aureus count.

Impact on the survival of Lactobacillus and Bifidobacterium

Batches of sterilized 5 ml DeMan- Rogosa-Sharpe (MRS) both samples were prepared then 5 ml of each commercial sample was added separately into each MRS broth. Samples were then inoculated with active Lactobacillus reuteri (L. reuteri ATCC SD2112) and Bifidobacterium (B. bifidum ATCC 15696) to achieve final inoculum level of 6.0 Log CFU/ml. We selected these strains as both Lactobacillus and bifidobacteria make up an integral part of the healthy human intestinal flora. Samples were then incubated at 37°C for 4 h to determine the impact of energy drinks on the survival of Lactobacillus and Bifidobacterium. One milliliter from each sample was then withdrawn and diluted with 0.1% peptone water. The appropriate dilutions were plated onto duplicate selective agar medium. Samples were plated on MRS agar for the enumeration of Lactobacillus and on Bifidobacterium iodoacetate medium 25 (BIM-25) for the enumeration of Bifidobacterium.

Results and Discussion

Microbiological and Safety Quality Test

Table 1 shows the list of energy drinks tested. Our results showed that none of the commercial samples contain harmful bacteria. The results indicated the absence of E. coli, Salmonella and Staphylococcus aureus. The total bacterial count for most of the samples are very low (< 1 log CFU/ml). Only two tested samples that have bacterial population of approximately 2.0 Log CFU/ml. These samples have low caffeine concentrations and higher pH values compared to other samples which could be the reason of survival of bacterial population. The initial biochemical analysis from these two samples indicated the presence of Bacillus which is common spoilage bacteria in soft drinks.

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Table1:

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Table 1. List of energy drinks, quantity of caffeine, total bacterial count and pH values.

Impact on the survival of Lactobacillus and Bifidobacterium spp.

All test energy drink showed lethal effect on both Lactobacillus and bifidobacterial strains tested as the bacterial count decreased to below 2.0 log CFU/ml. With only three products (17-19), the populations of Lactobacillus and Bifidobacterium spp. were approximately 2.5 log CFU/ml.

In this study we evaluated the microbiological quality and safety of 20 most common energy drinks available in the local stores in Saudi Arabia. The samples were selected based on the size of the samples and affordability to purchase the products. Our results confirmed the safety and quality of all tested products as they showed low level of total bacterial population and absence of common spoilage and pathogenic bacteria. However, our findings showed that energy drinks could have negative impact on human health as these drinks demolish the presence of natural flora such as Lactobacillus and Bifidobacterium spp. in human gastrointestinal tract. These bacteria are important to the health and contribute to different aspect of human health. Regular consumption of energy drink could have a long term negative impact on health and consumers should be educated about such effect to maintain healthy life style.

Limitations

During this study we faced several challenges that limit the scope of the work, we were only be able to collect 20 different brand of energy drinks from local stores in Riyadh. This is due to the restriction in sales regulations. Availability of energy drinks varied from region to region limits the sample size needed to represent the large population. We understand that this is a small representation of the energy drink products. However, this study could open the opportunity for possible collaboration with other countries and exam wide range of commercial products.

Acknowledgments

This project was supported, in part, by King Saud University, Deanship of Scientific Research (NFG- 15 -01- 02), and College of Sport Sciences and Physical Activity, Research Center.

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