Microbial contamination associated with consumption and the growth in plastic bottled beverage

Molecular microbiological profiling of bottled unsweetened tea beverages: a screening experiment

To explore the potential storage and safety of drinking leftover bottled tea beverages from various manufacturers after direct drinking from bottles, we conducted a screening experiment on the growth of salivary bacteria in plastic bottles of tea. The diluted saliva samples from 10 participants were inoculated into the test bottled beverages, which resulted in bacteria, particularly former members of the genus Lactobacillus, growing in some green tea beverages with a neutral pH. In contrast, tea beverages with less bacterial growth contained Streptococcus spp., and the leftovers may be safe to store and drink again.

Profiling of the microbiota in the remaining sports drink and orange juice in plastic bottles after direct drinking

OBJECTIVES

The survival of bacteria in the sports drink and orange juice remaining in and at the mouth of bottles after direct drinking was examined after immediately drinking and incubation at 37°C for 24 h.

METHODS

Nine healthy participants were asked to drink approximately 100 mL of a plastic bottled sports drink or orange juice. The samples were cultured anaerobically at 37°C for 7 days. Genomic DNA was extracted from the resulting individual colonies, and bacterial species were identified using 16S rRNA gene sequencing.

RESULTS

The mean amount of bacteria in the remaining sports drink and orange juice, immediately after drinking, were (1.6 ± 2.3) × 10³ colony-forming units (CFU)/mL and (2.9 ± 3.3) × 10³ CFU/mL, respectively. Additionally, bacteria recovered from the mouths of the sports drink and orange juice bottles were (2.5 ± 5.5) × 10⁴ CFU/mL and (5.8 ± 2.4) × 10³ CFU/mL, respectively. Oral bacteria, such as Streptococcus, Actinomyces, Neisseria, and Rothia were found to be transferred in the sports drink and orange juice, and the bacteria were scarcely detected after incubation at 37°C for 24 h.

CONCLUSIONS

The bacterial levels differed significantly from the previously reported levels in bottled tea 24 h after drinking, suggesting that remaining drinks with low pH levels can be preserved for a longer period.

Profiling of Microbiota at the Mouth of Bottles and in Remaining Tea after Drinking Directly from Plastic Bottles of Tea

It has been speculated that oral bacteria can be transferred to tea in plastic bottles when it is drunk directly from the bottles, and that the bacteria can then multiply in the bottles. The transfer of oral bacteria to the mouth of bottles and bacterial survival in the remaining tea after drinking directly from bottles were examined immediately after drinking and after storage at 37 °C for 24 h. Twelve healthy subjects (19 to 23 years of age) were asked to drink approximately 50 mL of unsweetened tea from a plastic bottle. The mouths of the bottles were swabbed with sterile cotton, and the swabs and the remaining tea in the bottles were analyzed by anaerobic culture and 16S rRNA gene sequencing. Metagenomic analysis of the 16S rRNA gene was also performed. The mean amounts of bacteria were (1.8 ± 1.7) × 10⁴ colony-forming units (CFU)/mL and (1.4 ± 1.5) × 10⁴ CFU/mL at the mouth of the bottles immediately after and 24 h after drinking, respectively. In contrast, (0.8 ± 1.6) × 10⁴ CFU/mL and (2.5 ± 2.6) × 10⁶ CFU/mL were recovered from the remaining tea immediately after and 24 h after drinking, respectively. Streptococcus (59.9%) were predominant at the mouth of the bottles immediately after drinking, followed by Schaalia (5.5%), Gemella (5.5%), Actinomyces (4.9%), Cutibacterium (4.9%), and Veillonella (3.6%); the culture and metagenomic analyses showed similar findings for the major species of detected bacteria, including Streptococcus (59.9%, and 10.711%), Neisseria (1.6%, and 24.245%), Haemophilus (0.6%, and 15.658%), Gemella (5.5%, and 0.381%), Cutibacterium (4.9%, and 0.041%), Rothia (2.6%, and 4.170%), Veillonella (3.6%, and 1.130%), Actinomyces (4.9%, and 0.406%), Prevotella (1.6%, and 0.442%), Fusobacterium (1.0%, and 0.461%), Capnocytophaga (0.3%, and 0.028%), and Porphyromonas (1.0%, and 0.060%), respectively. Furthermore, Streptococcus were the most commonly detected bacteria 24 h after drinking. These findings demonstrated that oral bacteria were present at the mouth of the bottles and in the remaining tea after drinking.

[Evaluation of Microbial Spoilage in PET Bottled Soft Drinks by Direct Drinking]

In order to evaluate microbial growth in opened PET bottled soft drinks, inoculation tests were carried out using type and reference strains of various microorganisms. Microorganisms were inoculated into a 500 mL PET bottle containing 250 mL of various soft drinks followed by incubation until 1 week at 4, 25, 35℃ without shaking, and 35℃ with shaking. The microbial counts were measured over time and compared with the results of the previous study "Studies on Contaminants in Soft Drink"^2)-4). As a result, similar growth patterns were observed in the combination of tomato juice with Lactobacillus fermentum, sports drink with Candida albicans, and mineral water with Klebsiella pneumoniae. However, in green tea, mixed herb tea, orange juice and coffee with milk, the growth of microorganisms generally tended to be weaker than those of the previous studies. It was considered that components in the soft drinks inhibited the growth of the microorganisms. From the above results, the proliferative properties of type and reference strains in soft drinks were clearly different from the spoiled soft drinks isolates. The results in this study indicated that attention must be paid in the safety evaluation.

[Evaluation of Hygiene in Dry Powder Steroid Drug Inhalers Used by Elderly Asthma Patients]

Dry powder inhalers (DPI) are frequently used by asthmatic patients, and the usage rate increases every year. The pharmacists at our hospital provided initial inhalation instructions on how the inhaler must be used but did not elaborate on the cleaning of the device. Therefore, the cleaning status of the inhaler is unknown, and there is a possibility of bacterial growth. This study investigated the cleaning status and hygiene of steroid drug inhalers used by elderly asthma patients. We administered a questionnaire to investigate the inhaler cleaning status after inhalation, and conducted a cross-sectional survey on hygiene using ATP measurement and bacterial culture examination. Considering the responses by 53 patients, it became clear that the ATP values of patients who answered "never cleaned" after inhalation were significantly higher than those who answered "cleaned every time". Moreover, some bacteria were detected in 62% of inhalers; 4 patients' inhalers contained bacteria other than normal oral microbial flora. In conclusion, because the inhalers used by elderly patients are in poor hygienic conditions, we must give cleaning instructions accordingly. We believe that it is necessary to give proper medical instructions along with instructions on the cleaning method with dry cloth.

Profiling of microbiota in liquid baby formula consumed with an artificial nipple

It is suspected that oral bacteria are transferred to the liquid baby formula through the artificial nipple and multiply in the bottle after feeding. In the present study, in order to understand the influence of bacteria on liquid baby formula after feeding, the transfer of oral bacteria through artificial nipples and their survival in liquid baby formula were examined immediately after drinking as well as after storage at 4°C for 3 h. Four healthy human subjects (20-23 years old) were asked to drink liquid baby formula (Aptamil^®, ca. 50 mL) from baby bottles using artificial nipples. Samples of the liquid baby formula (immediately after drinking and 3 h later) were inoculated onto blood agar plates and incubated anaerobically at 37°C for 7 days. Salivary samples from each subject and 6 newborn infants were also cultured. Genomic DNA was extracted from individual colonies, and bacterial species were identified by 16S rRNA gene sequencing. The mean amounts of bacteria (CFU/mL) were (3.2 ± 3.0) ×10⁴ and (3.4 ± 3.3) ×10⁴ immediately after drinking and 3 h later, respectively. Streptococcus (41.6 and 40.5%), Actinomyces (24.3 and 21.5%) and Veillonella (16.2 and 11.0%) were recovered from the samples immediately after drinking and 3 h later, respectively. On the other hand, Streptococcus (38.9%), Actinomyces (17.1%), Neisseria (9.1%), Prevotella (6.9%), Rothia (6.9%) and Gemella (5.1%) were predominant in the saliva of adult subjects, and Streptococcus (65.2%), Staphylococcus (18.5%), Gemella (8.2%) and Rothia (5.4%) were predominant in the saliva of infant subjects. From these findings, oral bacteria, e.g., Streptococcus, Gemella and Rothia, were found to transfer into the liquid baby formula through artificial nipples, and the bacterial composition in the remaining liquid baby formula was found to resemble that of human saliva. The bacterial levels were similar between immediately after drinking and when stored at 4°C for 3 h, suggesting that the remaining liquid baby formula may be preserved in a refrigerator for a specified amount of time.

[Microbial Growth in Unfinished Beverages in Plastic Bottles and the Awareness of Nursing Students in a University about Microbial Contamination]

OBJECTIVES

The purposes of this study were to clarify the microbial growth when drinking a beverage directly from its plastic bottle using models under consumption conditions characteristic for nursing students in a university and their awareness about microbial contamination in unfinished beverages in bottles.

METHODS

Three types of bottled beverages were tested: mineral water, Japanese green tea with catechin, and a lactic acid beverage. The ways of drinking were putting the entire lip of a bottle into the mouth (type A) and holding half of the lip out of the mouth (type B). The bottles were kept at room temperature for 8 hours. Samples from unfinished beverages were cultured to detect viable bacteria. An anonymous questionnaire was sent to 324 nursing students of a university, among which 279 responded.

RESULTS

The number of viable bacterial cells was larger in type A of drinking than in type B. It increased in mineral water until 2 hours, after which it remained the same. It decreased in Japanese green tea with catechin and the lactic acid beverage. However, even the smallest number exceeded the standard number for drinking beverages. Among the nursing students, 62.7% were aware of microbial contamination in unfinished beverages, but despite this awareness, they did not consume their beverages as soon as possible.

CONCLUSION

It is necessary to provide the nursing students with health education on the safety of partially consumed bottled beverages with respect to food hygiene, even if microorganisms do not grow in some types of beverages.

Characteristics of bacterial and fungal growth in plastic bottled beverages under a consuming condition model

Microbial contamination in unfinished beverages can occur when drinking directly from the bottle. Various microorganisms, including foodborne pathogens, are able to grow in these beverages at room temperature or in a refrigerator. In this study, we elucidated the characteristics of microorganism growth in bottled beverages under consuming condition models. Furthermore, we provide insight into the safety of partially consumed bottled beverages with respect to food hygiene. We inoculated microorganisms, including foodborne pathogens, into various plastic bottled beverages and analysed the dynamic growth of microorganisms as well as bacterial toxin production in the beverages. Eight bottled beverage types were tested in this study, namely green tea, apple juice drink, tomato juice, carbonated drink, sport drink, coffee with milk, isotonic water and mineral water, and in these beverages several microorganism types were used: nine bacteria including three toxin producers, three yeasts, and five moulds. Following inoculation, the bottles were incubated at 35°C for 48 h for bacteria, 25°C for 48 h for yeasts, and 25°C for 28 days for moulds. During the incubation period, the number of bacteria and yeasts and visible changes in mould-growth were determined over time. Our results indicated that combinations of the beverage types and microorganism species correlated with the degree of growth. Regarding factors that affect the growth and toxin-productivity of microorganisms in beverages, it is speculated that the pH, static/shaking culture, temperature, additives, or ingredients, such as carbon dioxide or organic matter (especially of plant origin), may be important for microorganism growth in beverages. Our results suggest that various types of unfinished beverages have microorganism growth and can include food borne pathogens and bacterial toxins. Therefore, our results indicate that in terms of food hygiene it is necessary to consume beverages immediately after opening the bottle.