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

Abstract

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.