Asaia sp., an Unusual Spoilage Organism of Fruit-Flavored Bottled Water

Abstract

A gram-negative bacillus was isolated from a batch of fruit-flavored bottled water, which had spoiled as a result of bacterial overgrowth (>10 6 CFU/ml). The spoilage organism was extremely difficult to identify phenotypically and was poorly identified as Pasturella sp. (78.7% identification profile) employing the API 20NE identification scheme, which gave the profile 5040000. Molecular identification through PCR amplification of a partial region of the 16S rRNA gene followed by direct automated sequencing of the PCR amplicon allowed identification of the organism. Due to the sequence identity (100%) between the spoilage organism and a reference strain in GenBank, the spoilage isolate was considered to be an Asaia sp., a recently described genus and member of the acetic acid bacteria. This is the first report of Asaia sp. causing spoilage of a foodstuff and highlights the benefits of molecular identification techniques based on 16S rRNA gene sequences in the identification of unusual spoilage organisms.There has been a gradual increase in demand for bottled water in the United States over the past 20 years, which has been exacerbated by public health scares relating mainly to waterborne outbreaks of human cryptosporidiosis caused by Cryptosporidium parvum. Furthermore, a recent study has demonstrated a high consumption (40%) of bottled water by human immunodeficiency virus-positive patients (2). To date, there have been relatively few reports employing the use of molecular identification methods, particularly the use of rRNA identification techniques, to identify contaminating bacterial and fungal agents in bottled water. We report an occurrence of spoilage in fruit-flavored bottled drinking water, which was isolated during production and prior to distribution. Our aim was to employ such molecular techniques to identify the bacterial spoilage organism, as phenotypic methods were unable to identify the organism.Microbiological examination was performed on a batch of fruit-flavored bottled water to determine the causal spoilage organism. The spoiled product was turbid (equivalent to McFarland standard 5) and had a characteristic sour odor, with a pH of 3.5. Quantitative microbiological examination on Plate Count Agar (Oxoid CM; Oxoid Ltd., Basingstoke, England) at 30°C for 48 h demonstrated the presence of a pure culture (Ͼ10 6 CFU/ml) consisting of a single and characteristic morphotype from which a single colony was purified, yielding an unidentified gram-negative rod, with no other bacteria or fungi cultured from the spoiled drink. The isolation of this morphotype from the spoiled fruit drink was repeated on further culture of the fruit drink. The spoilage isolate grew at 22 and 30°C but failed to grow at 37°C. It was catalase positive and oxidase negative, with translucent, pale pink, shiny, smooth colonies which were raised with an entire edge. The colonies were extremely small (approximately 1 to 2 mm in diameter), and the isolate was relatively

Bacteria of the genus Asaia stably associate with Anopheles stephensi , an Asian malarial mosquito vector

“…(17,18,23). Strains of the genus Asaia have also been isolated in bottled fruitflavored drinks (24), and A. bogorensis was recently isolated from the blood of an i.v. drug user in Finland (25).…”

Acetic Acid Bacteria – Taxonomy, Ecology, and Industrial Application

“…Bakterie octowe izolowane są także z wadliwych napojów fermentowanych, smakowych wód mineralnych i napojów bezalkoholowych [20,21,27]. Niekorzystna działalność bakterii AAB w winie lub piwie, polegająca na utlenianiu etanolu do kwasu octowego, powoduje pojawienie się w napoju obcego zapachu i posmaku.…”

Quillaja saponaria Saponins with Potential to Enhance the Effectiveness of Disinfection Processes in the Beverage Industry

“…was investigated in liquid minimal medium (0.3% (w/v) (NH 4 Multiplates were incubated using a UV-vis MULTISKAN GO spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA) at 25 • C for 24 h. Measurements of absorbance were carried out automatically every 1 h at a wavelength of 540 nm. The MICs were defined as the lowest concentrations of disinfectants at which there was no growth of Asaia spp.…”

“…contamination in soft drinks. However, flowers and fruits from Asia have been suggested as the source [1][2][3][4]. Asaia spp.…”