Microbial Contamination Levels of Fresh Vegetables Distributed in Markets

Transcription

1 J. Fd Hyg. Safety 20(1), (2005) m sƒ Á Á xá Á y*á ³y**Á½ š***á w****á½ Áw w tœw * w **w w ***w œw **** t t Microbial Contamination Levels of Fresh Vegetables Distributed in Markets Jin-Won Choi, Shin Young Park, Ji-Hye Yeon, Min Jeong Lee, Duck Hwa Chung*, Kyu-Ho Lee**, Min-Gon Kim***, Dong-Ha Lee****, Keun-Sung Kim, and Sang-Do Ha %FQBSUNFOUPG'PPE4DJFODFBOE5FDIOPMPHZ$IVOH"OH6OJWFSTJUZ*(ZFPOHTBOH/BUJPOBM6OJWFSTJUZ **)BOLVL6OJWPG'PSFJHO4UVEJFT***,PSFB3FTFBSDI*OTUJUVUFPG#JPTDJFODFBOE#JPUFDIOPMPHZ ****,PSFB'PPEBOE%SVH"ENJOJTUSBUJPO ABSTRACT This study monitored and compared the contamination levels of total aerobic bacteria, coliforms, Escherichia coli, and L. monocytogenes of either lettuce, sesame leaf, or cucumber sampled from either 15 super markets(sm) or 21 traditional markets(tm) located in both Seoul and the southern part of Gyunggi. Contamination levels of total aerobic bacteria and coliforms in lettuce, sesame leaf, or cucumber from SM or TM were not (p>0.05) significantly different. The highest contamination levels of total aerobic bacteria were observed in lettuce and followed by sesame leaf and cucumber. The contamination levels of total aerobic bacteria in lettuce, sesame leafs, and cucumbers were 7.01±0.14 g(sm) and 7.10±0.11 g (TM), 6.69±0.20 g(sm) and 6.44±0.13 g (TM), and 5.37±0.25 g (SM) and 5.27±0.19 g (TM), respectively. A similar pattern of contamination rank was observed with the coliforms in three vegetables as was observed with the total aerobic bacteria. E. coli were not significantly (p>0.05) different between SM and TM and isolated over 30% in lettuce and sesame leaf and below 10% in cucumbers. L. monocytogenes were not detected in all three vegetables(nd: cucumber <3 g, lettuce and sesame leaf <10 g). The microbial contamination levels determined in the present study may be used as the primary data to execute microbial risk assessment of fresh vegetables. Key words: Lettuce, Sesame Leaf, Cucumber, Listeria monocytogenes, Escherichia coli 2001 ù š t w 1z wš š šwš., y w w w ú ƒ š, š ƒœ t t ywš y y ³ m ƒ ƒw. š w m y ql w y «š. w w s³,, à š w ƒ t(ready-to-eat food) ¾ ù š Author to whom correspondence should be addressed. w š ù, ƒ ƒ. 1) w Salmonella spp., Echerichia coli O157:H7, Listeria monocytogenes, Shigella sonnei³ ù w ƒ. 2~5) w, à x l v w t w ³ Listeria monocytogenes y» ³, ³ E. coli d, w k q w wz wsƒ(microbial risk assessment, MRA)» y w. x t ( 43

2 44 CtyV y6s tp fw û,, s,, s )»û 3 (, sk, ) 15 x 21, Ã, w. w z ƒƒ ³ stomacher bag ice box 2 ü x w., à w (10 g) à (g), (30 g) ³ 90 ml ³ stomacher bag stomacher(elmex SH- II M, Tokyo, Japan) w 1 ³ yw ³ w 10 w. ³ w» w 8.0 g NaCl, 0.2 g KCl, 1.15 g Na 2 HPO 4 Á7H 2 O, 0.2 g KH 2 PO 4 1,000 ml 1N NaOH ƒw ph 7.2 w autoclavingw z w. y» ³ ³ y» ³(total aerobic bacteria) ³ (coliforms) w w 0.5 ml ³ 4.5 ml w ¾ -6 wš 1 mlƒ ¼ petri-dish ƒƒ ml tryptic soy agar(tsa, Difco, USA) violet red bile agar(vrba, Difco, USA) z 37 C o w. z standard plates count(spc) w ƒƒ x colony w colony-forming unit(cfu)/g ùkü. ³(Escherichia coli) E. coli 3M z (3M Microbiology Products, USA) Petrifilm TM E. coli count(pec) w w 1 ml film w 37 C o w. z»s ƒ blue colony E. coli wš SPC w g ùkü. Listeria monocytogenes Listeria monocytogenes USDA 6) w w. 25 g w 225 ml UVM(University of Vermont Medium)-Modified Listeria ³ (Difco, USA) ƒw z 2 ³ y k 30 o C 24 w. 1 ³ 1 ml w Fraser Listeria (Difco, USA) 9 ml w 35 o C 24~48 2 ³ w. ³ 1 ml modified oxford agar w ³ w spreadingw z 30 C o 24~48 w. y 0.6% yeast extractƒ sw tryptic soy agar(tsa, Difco, USA) w 35 C 24~48 o w. z colony w w š colony kw API Kit w L. monocytogenes y w. m ³ g ùkü, SAS m v, version ) General Linear Models (GLM) procedure PDiff(P-value Differentiation) option w w least square mean separation E. coli w m Chi-square 8) w. m p<0.05. š m, Ã, y» ³ ³ w s³, Ã, ƒ ƒ v t t y ƒ w. wr, x t m m ƒ þ m y ƒš ù q m ù t m w xk wš. x, à y» ³ ³, w Table 1 ùkü. x m, Ã, y» ³ m ù(p>0.05), Ã,. s³ 7.01~7.10 g g š à s³ 6.44~6.69 g 4.86~7.79 g s³ 5.27~ 5.37 g 3.48~6.57 g. à w t m m ƒ y» ³ ³ ƒ û š q à y» ³ š 7.85~8.01 (g) 7.65~7.79 (g) q w t ƒeƒ

3 Fthƒ gtfw6 y fxtyf t yep pw q9ƒp suprp fgwp 7t ƒtg pityffƒvp 45 Table 1. Total aerobic bacteria and coliforms in 3 kinds of vegetables distributed in markets Total aerobic bacteria ( g) Coliforms ( g) Vegetables Market MeanÛSE Minimum Maximum MeanÛSE Minimum Maximum Lettuce Sesame leaf Cucumber SM 1) 7.01Û Û TM 2) 7.10Û Û SM 6.69Û Û TM 6.44Û Û SM 5.37Û Û TM 5.27Û Û ) SM=Super Market, 2) TM=Traditional Market.. ³ ƒ 10 7 ~10 g 8 t w t w» w ³ w k ƒ j. 16) g 5,9) Erwinia, Psedomonas, Enterobacter, lactic acid bacteria r t q 10,11) Listeria monocytogenes, Clostridium botulinum, Aeromonas hydrophila, Salmonella, E. coli O157:H7, Yersinina enterocolitica Campylobacter jejuni r t ³. 12) x m, Ã, ³ (Coliforms) m (p>0.05) w, Ã,. s³ 6.26~6.44 g 5.17~7.40 g š à s³ 5.68~5.71 g 4.19~7.05 g s³ 3.65~4.01 g g. Ã, ³ ü ³ w Salmonella Shigella ³ ƒ üs wš» x š q. m, Ã, ³ ³(E. coli) t t ³ t x. Table 2 x m, Ã, ³ ù (p>0.05) à 33~53% g ƒ, 29~33% Table 2. Escherichia coli in 3 kinds of vegetables distributed in markets Vegetables Lettuce Sesame leaf Market Positive no./total (%) Escherichia coli Contamination level( g) SM 1) 5/15(33%) TM 2) 6/21(29%) SM 8/15(53%) TM 7/21(33%) SM 1/15(7%) 1.38 Cucumber TM 2/21(10%) ) SM=Super Market, 2) TM=Traditional Market g š 7~10% g ƒƒ ùkû. ù tœ Á ƒœt Á u Á 13) r p ³ ³ wš ù w ³ ¾. ³ wš E. coli» 10 2 g x» ü ù à š g x» w 14), Ã, ³» y z q. Ã, L. monocytogenes, Ã, ƒ œ t(minimally processed food) xk m š ƒœ w z ü ³ š» t ƒw» j ³ sw

4 46 CtyV y6s tp fw m ƒ v w. p Listeria monocytogenes ³ ƒ 4 þ ƒ w 15,16) Listeriosis k. x ¾, qw, 17), 18) silage, 19),, 20) L. monocytogenesƒ Á, eù ƒ listeriosis q» w. 21) þ w L. monocytogenes w w, x, Ã, v L. monocytogenes x (data not shown). L. monocytogenes ³ q w 10 2 g ¾ x w ù 14) 25 g t w L. monocytogenes zero tolerance( ) ³ w w w. 14), Ã, L. monocytogenes ù, ù» w w» w L. monocytogenes w ³» v w q. ww» û x m, Ã, w t ³ L. monocytogens ù y» ³, ³ ³ mw ù(p>0.05) m 3ƒ t k q. wsƒ(mra)» y wz m y w ³, w³s w w w ƒ v w q. 2004» w (03-PJ1-PG1-CH ). x w» w m, Ã,»û 15 x 21 samplingw y» ³, ³, Escherichia coli Listeria monocytogenes sƒw. x, Ã, y» ³ ³ ƒ (p>0,05). ù 3ƒ y» ³, Ã, ùkû ƒƒ s³ 7.01±0.14 g( x) 7.10±0.11 g( ), 6.69±0.20 g( x) 6.44±0.13 g( ), 5.37±0.25 g( x) 5.27±0.19 g( ) ³ w. E. coli 3ƒ (p>0.05) à x 30% ù, 10%. L. monocytogenes (ND: <3 g,, à <10 g). d wsƒ(mra)v» y. š x 1., ½,,, w,,»y: w w l, w t wz, 16, (2001). 2. Itoh, Y., Sugita-Konishi, Y. Kasuage, F., Iwaki, M., Hara- Kudo, Y., Saito, N., Noguchi, Y., Konuma, H. and Kumagai, S.: Enterohemorrhagic Escherichia coli O157:H7 Present in Radish Sprouts, Appl. Environ. Microbiol., 64, (1998). 3. Hedberg, C.W., Angulo, F.G., White, K.E., Langkop, C.W., Schell, W.L., Stobierski, M.G., Schuchat, A., Besser, J.M., Dietrich, S., Helsel, L., Griffin, P.M., McFarland, J.W., Osterhorm, M.T. and The Investigation Team: Outbreaks of

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