The microbiological quality of drinking water supplies of Izmir City: the incidence of Yersinia enterocolitica

International Jounml of Food Microbiololff, 13 (1991) 6 9 - 7 4 © 1991 Elsevier Science Publishers B.V. 0168-1605/91/$03.50

69

FOOD 00396

Short communication

The microbiological quality of drinking water supplies of izrnir City: the incidence of Yersinia enterocolitica ~ahika Aktu~ G~niil and Mehmet Karapmar Ege Uni~wrsity,Facultyof Engin~,mg Food EngineeringDcparrme~ [:mir,Turkey (Received 27 August I990; e__~ep_ted 31 December 1990)

A mud of 100 water samples collected from piped public ~oplic~ wells with and without motor pumps, springs and commercially bottled ~ wau,,'s were m i ~ examined. In order to determine microbiolol~d quality, aerobic bact~al and ce~iform counts were estimated and the presence of E.sckcr/dUa co// and Y ~ a a u ~ wu mvestipted. Of the nmpim tmte~ 85 of them met the specifications set by TFR ('rufldala Food l h l p d a ~ ) for colilm'ms" wlaweu 72 of them met the specifications for aerobic bacte~ The number of samples containing Y. enteroco//t/ca and E. co// w e ~ found to be 6 and 5, respectively. Key words: Yemma enterocolitica; ~ c k / a

co//; Drinking water; Microbiolo$ical quality of water

lneroduelion Yersinia enterocolitica is a h u m a n pathogen which has been associated with acute and chronic gastroenteritis, septicemia, wound infections and other clinical syndromes. This organism has been increasingly implicated in food and water-borne outbreaks and has been isolated from water and a variety of foods including dairy products, meat products and vegetables (Stern and Pierson, 1979; Shayegani et al., 1981; Stem, 1981; Vidon and Delmas, 1981; Tacket et al., 1984; Delmas and Vidon, 1985; Fukushima et al., 1987; Schiemann, 1987). The present investigation deals with the incidence of Y. enterocolitica and E. coil in the drinking water supplies of | z m i r city. In order to determine the microbiological quality of the water supplies, aerobic bacterial and coliform counts were also estimated.

Coo',nrpe,mk,~ mddv,n~: M. Karapmar, ~ Depm'ummt. I~rnova..Llunir35101, Turkey.

University, Faculty of F.nSineerin~ Food ~,,~,.'~n~

70 Materials and Methods

Drinking water samples A total of 100 water samples collected from different sources consisting of 50 from piped public supplies, 15 from wells with motor pumps, 2 from wells without motor pumps, 7 from springs and 26 commercially bottled spring waters was examined. The samples other than the commercially bottled spring water were collected in sterile 100-ml bottles, and kept at refrigerator temperature until analysis. The time between the sample collection and processing did not exceed three hours. Microbiological analyses The water samples were analysed for aerobic bacteria, coliform and E. coli counts and for the presence of Y. enterocolitica. The pH of each water sample was also determined. The aerobic bacterial counts were determined according to Gilliland et al. (1976) whereas the methods described by Harrigan and McCance (1966) were used for the examination of coliforms and E. carl. To determine the presence of Y. enterocolitica, a two-step enrichment was carried out. 10 ml of the water sample was added to 90 ml of phosphate buffered saline (PBS) and incubated at 4 " C for 14 days for the cold enrichment procedure. 10 ml of PBS broth culture was then transferred to modified Rappaport broth for the selective enrichment and incubated at 22"C for 48 hours (Schiemann, 1982). The enrichment cultures were subcultured by ftrst taking 0.5 ml and mixing for a few seconds with 4.5 ml of 0.5% KOH in 0,5% NaCI (Aulisio et al., 1980) and then immediately streaking a loopful of this mixture on to cefsulodin-irgasan-novobiocin (CIN) agar and MacConkey-Tween 80 agar (Devenish and Schiemann, 1981; Lee, 1977). From suspect colonies the biochemical tests were performed (Anon, 1986).

Results and Discussion

The recommendations of the Turkish Food Regulation (TFR, Erco§kun, 1987) were used as a guideline in controlling the microbiological quality of water samples. According to the TFR, the aerobic counts of drinking and spring waters should not exceed 500 and 50 per ml of water, respectively, and 100 rnl of both types of water should not contain coliform bacteria. According to the same regulation, the pH of the drinking water and springs should be in the range of 6.5-9.2 and 6.5-8.5, respectively. Of the samples tested, all of them met the specifications by TFR for pH values. Of the samples tested, 85 met the specifications set by TFR for coliforms, whereas 72 of them met the specifications for aerobic bacteria. Ten samples were found to be out of the ranges set for both criteria. The numbers of sample containing Y. enterocolitica and E. coli were found to be 6 and 5, respectively (Table I). Sources of samples in which Y. enterocolitica was isolated were 2 wells with

71 TABLE I Microbiological quality of water samples Type of water

No. of Eamples

Percentage of samples which did not meet TFR

Percentage of samples which contain

coli/orm

Y. entcrocohtica

aerobic

both criteria

E. coti

count

Piped public u~opfies Wells with motor pumps Wells without motor pumps Spring waters Commercially bottled spring waters Total

50

4

16

2

2

0

15

33

47

27

13

7

2 7

50 86

100 57

50 43

0 43

50 43

26 100

4 15

27 28

4 10

0 6

0 5

pumps, 2 springs and 1 piped public supply. Five samples contaminated with Y. enterocoiitica contained E. coli or coliforms (Table II). One sample which contained Y. enterocolitlca did not contain coliforms or £. co//. The recovery of Y. enterocolltica from waters which do not contain coliforms or high bacterial counts has also been reported by other workers (Langeland, 1978; Schiemann, 1978; Weber et al., 1981). Y. enterocolitica has been isolated frequently from drinking, surface and well waters (Harvey et al., 1976; Highsmith et al., 1977; Langeland, 1978; Aldova et al., 1981; Shayegani et al., 1981; Weber et al., 1981; Meadows and "Snudden, 1982; Maleszewska et al., 1988). Although the epidemiology of Y. enterocolitica infections has not been completely understood, water may be a significant reservoir, since this organism is widespread in a variety of water samples and has been implicated as a causative agent of several water-borne outbreaks (Stern and Pierson, 1979; Tacket et al., 1985; Thompson and Gravel, 1986). Therefore, the current water hygiene quality

TABLE

II

The nucrobiolo~cal quality of water samples o o n ~

Y. enterocolitica

Type of water conuunmg Y. enterocolitica

Aerobic bacteria/ml

Coliform bacteria/100 ml

£. co// cotmt/100 ml

Well with motor pump Well with motor pump Spring Spring Spring Piped public supply

1.8X103 3.6 X 10 z 4.8 x 102 4.2 x 102 6.2 × 102 1.5 X 102

n.d." a 93 93 240

n.d. n.d. n.d. n.d. 93 n.d.

• n.d.. not detected.

4

72 p a r a m e t e r s m a y b e i n s u f f i c i e n t as i n d i c a t o r s o f the p r e s e n c e o f Y. e n t e r o c o l i t i c a . Y. e n t e r o c o l i t i c a s h o u l d a l w a y s be c o n s i d e r e d w h e n a w a t e r - b o r n e o u t b r e a k w i t h a n u n k n o w n e t i o l o g y occurs.

Acknowledgement The financial support of Ege University Research Foundation is gratefully acknowledged.

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