Research Article
Microbial Growth and Chemical Analysis of Mineral Contents in Bottled Fruit Juices and Drinks in Riyadh, Saudi Arabia

Suaad S. Alwakeel and Eman Abdullah Hamad Al-Humaidi

Research Journal of Microbiology, 2008, 3(5), 319-325.

Abstract

This study aimed to determine the clinically important levels of minerals in bottled fruit juices and drinks and to determine the microbial contamination of commercially available bottled fruit juices and drinks from different supermarkets in Riyadh, Saudi Arabia. Commercially available bottled fruit juices and drinks were brought from different supermarkets in Riyadh, were examined microbiologically and mineral contents were determined by atomic absorption spectrophotometry. A total of 150 specimens (3 replicates of a total 50 samples) were examined for microbial growth on six different culture media (BAP, NA, MacConkey, CAP, Salmonella Agar and PDA). A total of 43 (28.7%) different colonies were seen on different fruit juices. Bacillus cereus was the most common isolate in all types of fruit juices. Other isolates included Bacillus subtilis, Bacillus polymyxa, Chryseomonas luteola, Tatumella ptyseos, Streptococcus lactis and Candida sp. None of the specimens taken from softdrinks and power drinks showed any microbial growth after incubation for 48 h in all six environmental plates used. Specimens from mixed juice with milk showed microbial colonies in 3 out of 10 specimens with Lactobacillus sp., Streptococcus lactis and Lactobacillus casei. The mineral contents of 8 specimens of fruit juices had iron content within the maximum allowed concentration. As to potassium content, 7 of 8 (87.5%) of the samples had potassium content >10 ppm. Five of 8 (62.5%) samples had sodium content >20 ppm, 7 of 8 (87.5%) had aluminum content >0.2 ppm, 4 of 8 (50%) had lithium content >0.2 ppm, 7 of 8 (87.5%) had magnesium content >30 ppm, 4 of 8 (50%) had manganese content >20 ppm, all 8 contained lead >0.2 ppm and 7 of 8 (87.5%) have zinc content >5 ppm. Commercially sold fruit juices in Riyadh, Saudi Arabia should be further investigated and regulated since they contain dangerous organisms and minerals which are toxic to the body.

ASCI-ID: 83-278

http://www.herbshop.com/miniguide.htm.).

Other inorganic toxic substances such as aluminum (Al) and lead (Pb) are not important for human nutrition. It can have toxic effects even in small qualities (CPMC, 1996; Ponessa, 1996).

This study was designed to determine the clinically important levels of minerals in bottled fruit juices and drinks and to determine the microbiological growth and content of commercially available bottled fruit juices and drinks in Riyadh, Saudi Arabia.

MATERIALS AND METHODS

Commercially available bottled fruit juices and drinks were bought from different supermarkets in Riyadh, Saudi Arabia in April 2007 and were examined microbiologically and mineral contents were analyzed.

Samples

All samples were bought with their security seals untampered and ensured were in their required storage temperatures with their expiry dates checked. Samples were taken to the microbiology and toxicology laboratories of Girls College of Education in Riyadh, Saudi Arabia for analysis.

Microbiological Analysis
Fifty specimens of bottled juices (pasteurized) and drinks were collected from supermarkets from different areas of Riyadh city, Saudi Arabia. Under sterilized conditions, 1 mL of each specimen were extracted and placed on Blood Agar plate, Nutrient Agar, MacConkey Agar, Chocolate Agar and Potato Dextrose Agar (PDA) for fungal growth. One milliliter of each specimen was diluted in 99 cm³ of sterilized distilled water and 1 mL of the mixture was incubated at 30°C for 48 h. Three replica of each specimen were prepared. Identification of microorganisms was done using the API 20E system (Analytical Profile Index, Biomerieux, Durham, NC, USA).

The same method was followed for 20 specimens of fizzy softdrinks. Containers were left open in an incubated environment for 2 h to allow escape of gases. Analyses were commenced provided gases were ensured to have escaped from each specimen.

The same procedure was applied using 10 specimens taken from commercially available powerdrinks.

The same procedure was applied on 10 specimens taken from juices fortified with milk.

Chemical Analysis of Mineral Contents in Fruit Juice Specimens
Mineral contents were determined from 8 fruit juice specimens. Minerals included Fe, K, Mn, Pb, Zn, Al, Li and Mg. Samples were prepared by mixing 20 mL of juice in a 100 mL volumetric flask with 10 mL of HCl then make up to volume with water. Mixtures were shaken well, transferred to centrifuge tubes and centrifuged to remove solid particles. In cases of elements with high concentrations, further dilutions were made so that the final solution contains 5% HCl. The juice samples were hydrolyzed by a strong acid, which allows the preparation of many samples at one time, filtered and then analyzed by atomic absorption using Unicam 929 atomic absorption spectrophotometer (Unicam Atomic Absorption, Cambridge, UK).

RESULTS

Microbiological Analysis
Microbial contamination in pasteurized bottled fruit juices samples. A total of 150 specimens (3 replicates of a total 50 samples) from 10 different juice types were tested for microbial growth on six different culture media (BAP, NA, MacConkey, CAP, Salmonella agar and PDA). A total of 43 (28.7%) different colonies were seen on different fruit juices including mango juice, strawberry juice, berry juice, orange juice, apple juice, pair juice, tropical mixed fruit juice and fruit and milk juice. Bacillus cereus was the most common isolate in all types of fruit juices except from apple juice and mixed orange and carrot juice. Other isolates included Bacillus subtilis, Bacillus polymyxa, Chryseomonas luteola, Tatumella ptyseos, Streptococcus lactis and Candida sp. (Table 1, 2).

Microbial contaminants in fizzy softdrinks and powerdrinks samples. None of the specimens taken from softdrinks and power drinks showed any microbial growth after incubation for 48 h in all six environmental plates used.

Microbial contaminants in milk fortified fruit juices. Specimens taken from mixed juice with milk showed microbial colonies in 3 out of 10 specimens. The isolated colonies showed Lactobacillus sp., Streptococcus lactis and Lactobacillus casei (Table 1, 2).

Chemical Analysis of Mineral Contents of Fruit Juice Specimens
Table 3 shows the mineral contents of 8 specimens of fruit juices sold in different supermarkets in Riyadh, Saudi Arabia. All 8 samples had iron content within the maximum allowed concentration. As to potassium content, 7 of 8 (87.5%) of the samples had potassium content >10 ppm.

Table 1:	Isolated microorganisms and number of colonies in tested fruit juices in Riyadh, Saudi Arabia

Table 2:	Bacterial and fungal growth on different culture media for tested fruit juices in Riyadh, Saudi Arabia
Note: Entries signify the No. of colonies in specified culture media

Table 3:	Mineral contents of tested fruit juices (ppm) in Riyadh, Saudi Arabia
*: Dietary Guidelines for Americans (2005) and US-FDA (2006)

Five of 8 (62.5%) samples had sodium content >20 ppm, 7 of 8 (87.5%) had aluminum content >0.2 ppm, 4 of 8 (50%) had lithium content >0.2 ppm, 7 of 8 (87.5%) samples had magnesium content >30 ppm, 4 of 8 (50%) had manganese content >20 ppm, all 8 samples contained lead >0.3 ppm and 7 of 8 (87.5%) have zinc content >5 ppm.

DISCUSSION

Present study showed the presence of different species of bacteria namely, Bacillus cereus, Bacillus subtilus, Bacillus polymyxa, Chryseomonas luteola, Tatumella ptyseos, Streptococcus lactis and Candida sp. in supposedly bacteria-free commercially available fruit juices is of a concern. Their presence may pose risks to consumers’ health and should not be taken for granted.

Bacilus cereus is an emerging pathogen that causes invasive disease in immunocompromised patients (El-Saleeby et al., 2004). These bacteria can survive, grow and sporulate despite changes in water activity, pH and temperature (Jaquette and Beuchat, 1998; Collado et al., 2003). Whether the food or juice is improperly cooled or prepared, Bacillus cereus could grow because their spores survive cooking and can germinate (US-FDA, 2006). Bacillus cereus can cause diarrhea and emetic illness causing dehydration and possibly death.

Bacillus subtilis has been used in animal feed, baking, cleaning and wastewater, food and beverage because of its capability to produce alpha amylase, crackerase and neutral protease that works at higher pH and temperature range that relaxes dough to get uniform crackers and improve cracker flavors (http://www.bio-cat.com). However, in the preparation of this enzyme needs inactivation of the sporulating capability of B. subtilis using high pressurized conditions (Vasantha and Freese, 1979).

Tatumella ptyseos is a new member identified with Enterobacteriacea found in clinical specimens from the respiratory tract (Hollis et al., 1981). Chryseomonas luteola, a gram-negative bacillus is associated with nosocomial infections and Candida albicans can cause serious disease in humans (Chihab et al., 2004). Lactobacillus sp. is a probiotic bacteria which can provide opportunities for the prevention or treatment of inflammatory bowel disease (Pena et al., 2005). Lactobacillus casei is present in fermented dairy products and has beneficial properties for human health. In the human digestive tract, it prevents the establishment of ingested lactic acid bacteria (Oozeer et al., 2006). Streptococcus lactus is said to be a non-toxic microorganism that can be transformed by a plasmid used as an ice nucleating agent or a functionally equivalent protein capable of inducing ice nucleation, lowering the temperature of the mixture, thereby preserving products such as fruit juices to below -5°C (US Patent, 1993). This organism also produces E234 Nisin, a polypeptide antibiotic used in cheese and milk preservatives (http://www.elixirmre.com).

Minerals are important parts of drinking water and even fruit juices and are of both direct and indirect health significance. Sufficient evidence is now available to confirm that a certain minimum amount of minerals is desirable, since their deficiency have many negative health effects: diseases and possible aggression from toxic elements and bacteria. In present study results, our samples were supposedly within the required mineral contents as stated in their company’s levels. However, the variability of minerals and elemental contents is great from bottle to bottle. In fact, no two brands of bottled water were identical in their mineral content (http://www. opsi.gov.uk/legislation).

Minerals such as magnesium and zinc are just as critical to maintaining optimal health, or that, taken in excess, these minerals can be toxic. Iron is essential for blood cells; potassium is needed for a healthy nervous system, lithium for controlling emotions and anger, magnesium for effective muscle function, manganese necessary for protein and fat metabolism and zinc to enhance immunity and for reproductive function. However, when taken in amounts over the recommended maximum allowable range, they can be toxic to health. These effects occur in nervous system. Present study showed 7 out of 8 samples had aluminum levels above the maximum allowable value of 0.2 ppm. Another is the presence of lead in all of our tested samples is alarming. Aluminum, as a metal when present in our food, water supply and soil can induce individuals to suffer from aluminum toxicity. After years of accumulated exposure and storage in our body, it can result to brain degeneration and skeletal deformities (http://www.drpepi.com). It is believed that Alzheimer’s disease is related to aluminum toxicity (Derouesne, 2004). On the other hand, exposure to even minute amounts of lead should be avoided. Lead is highly toxic to humans especially in young children who love to drink fruit juices. It has no known physiologic value to humans. In children, even very low levels of exposure to lead can result to reduce IQ, learning difficulties, attention deficit disorders, behavioral problems, impaired hearing and kidney damage. In adults, it can increase BP and can cause fertility problems, nerve disorders, muscle and joint problems, irritability and memory or concentration problems (http://www.nsc.org/library/facts). These 2 identified metals are toxic to consumers and thus require further examination, verification and further testing of samples.

The results of our study have several implications for the consumption of these commercial fruit juices in Saudi Arabia. The differences in the mineral content for toxic substances should be further investigated since the issue of potability and safety may advertently harm consumers. It is therefore recommended that corresponding authorities should be vigilant in the issuance of permits and licenses in the manufacture and production of these products.

CONCLUSION

Further analysis of commercially sold fruit drinks should be done. Regulation in the issuance of permits to produce and sell these products should be under strict quality control to reduce and mitigate exposure to harmful microbes and toxic chemicals deleterious to consumers’ health.

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