dixon watercress

ResultsBased on PHLS microbiological guidelines for salad vegetables: less than 20Escherichia coli per gram is satisfactory, 20 - 100 represents the minimum standardfor consumption, and more than 100 is unacceptable.

DiscussionThe PHLS guidelines are based on Escherichia coli because the presence of thisbacteria indicates recent faecal pollution. Faecal pollution carries a risk of disease.

Traditional harvesting of watercress includes plant selection andlong term sustainability of the watercress beds. Plants withadventitious roots at the nodes are not picked, and this maycontribute to satisfactory bacteriological quality because smallgaps in roots are a known point of entry for bacteria includingEscherichia coli.

Recent research has shown that bacteria that enter lettuce rootscan be transported to the edible leaves.

Watercress beds reduce stream flow and can lead to deposition ofparticles including bacteria like Escherichia coli. This means thatthe risk of bacterial contamination of the plant is highest in denseareas and near stream banks.

ConclusionNon-traditional harvesting of watercress was clearly associated with poor qualityand a probable health risk. However, when watercress is harvested traditionally thequality was usually satisfactory.

It is recommended that watercress is harvested using traditional techniques. Thesetechniques are a simple and common sense approach that will decrease the risk offood borne illness, and ensure an ongoing supply of this healthy vegetable.

Ngaa aahua o te hauhake o naaianeia) Te waahi o te hao: Ngaa waatakirihi e taea ai te tata atu i haongi.Kaare he aha mehemea i te kai timutimu ngaa kararehe. I kato aingaa waatakirihi i ngaa takutai.

e) Te kohi pua: Kaare i aata kohia ngaa pua i katoa.

i) Te huarahi kato: I katohia, i huhuti ki te kaihao e piri tonu ana ngaapakiaka. I wetekina ngaa pakiaka kaatahi ka whiua.

o) Te huarahi horoi: Kaare ngaa waatakirihi i horoingia, ki te horoia,kua horoia ki te wai i huhuti ai eetehi atu waatakirihi.

Ngaa aahua o te hauhake kai i muaa) Te waahi o te hao: Kaare he kai timutimu.

e) Te kohi pua: Kaare he pakiaka i te pito o ngaa pua, ngaa pua o tewaatakirihi he kakau kaakariki, paapura raanei to te waatakirihi e tataana ki ngaa waahi takutai.

i) Te huarahi kato: I kato ai te waatakirihi i te 30 henemita kotahi tekakau.

o) Te huarahi horoi: Ko ngaa kaahui waatakirihi katoa kei raro i tekare o te wai e whakaatu ana i te ia o te wai. Ka wiriwiringia kiamakere te wai toenga i mua i te whakamautanga ki teetehi peekekirihou maa.

TimatangaKo te waatakirihi teetehi waahanga matua o te kai kua hauhaketia i mua. Ko te hao i teeneikai i whakatapua, engari kaare kee taua tapu e mahia ana inaaianei. Kua oti te rangahaumehemea e whai paanga ana te huakita o te waatakirihi e te momo hao i teenei kai.

Te Huakita o teWaatakirihi

Fluorescent labelledE. coli 0157:H7lurk inside lettuce.© Karl Matthews,Rutgers University

Of the 13 samples collectedusing traditional technique, 12were satisfactory, and 1 was ofminimum standard.

Of the 14 samples collected using non-traditional technique, 9 samples weresatisfactory, but 5 samples were unacceptableand therefore unsuitable for eating.

Microbiological quality ofnon-traditional

harvested watercress

64.20%

35.80%

n = 5 n = 9

SatisfactoryUnacceptable

Microbiological quality oftraditional

harvested watercress

8.40%

91.60%

n = 12

n = 1 SatisfactoryMinimumstandard

Features of Non-Traditional Harvestinga) Area selection: Watercress that was easily accessible was picked.No attention was paid to evidence of grazing animals in the area ofharvesting. Watercress picked from banks and riparian margins.

b) Plant Selection: No special care taken when plants were selected.

c) Picking Method: Each bunch was grabbed and pulled out of thewater towards the harvester with roots still attached. The rootswere ripped off and discarded.

d) Washing Method: Watercress not usually washed, but if washed,bunches were immersed in water that was exposed by the removalof the grabbed and ripped watercress.

Features of Traditional Harvestinga) Area Selection: No evidence of grazing animals.

b) Plant Selection: Absence of adventitious roots at nodes of plants,watercress in flower, green/purple watercress stalks and watercressclose to riparian margins.

c) Picking Method: Watercress picked as single stems ofapproximately 30cm.

d) Washing Method: Each formed bunch was submerged in flowingstream water with leaves facing the current. Submerged buncheswere agitated gently and after removal from the stream were givena good shake to remove excess water before packing upright in aclean plastic bag.

IntroductionWatercress is an important component of traditional harvested foods.Traditional techniques of harvesting encompass cultural awareness but nowadaysthis awareness is not always observed. A study was carried out to determine whetherthe bacteriological quality of harvested watercress was affected bythe method of harvest.

Bacterial Quality ofHarvested Watercress

Ngaa whakautuE ai ki te tohu a te huakita moo ngaa pua whenua, e mea ana, e iti iho i te 20 karamu ote huakita Escherichia coli e pai ana, 20-100 he aahua pai, aa, 100 raanei kaare i te pai.

KoorerotangaE haangai ana te tohu a te PHLS ki te huakita Escherichia coli naa te kitenga o te huakitae meatia nei kua para tiko. Ko nga para tiko ka taea te whakamate i te tangata.

Ko te tikanga hao o mua e ora ai te momo kai me toona waahi noho.Kaare ngaa pua e katongia mehemea he pakiaka, koinei pea teetehihuarahi e pai ake ai nga pua nei i te mea, ko ngaa whaarua pakupakuo te pakiaka e uru ai te huakita Escherichia coli.

Kua kitea i roto i ngaa rangahau o naa tata nei, ko ngaa huakita e uruai maa ngaa pakiaka reetihi, ka kawea tonutia ki ngaa rau. Ko te nohoa ngaa waatakirihi e puru ai te rere o te wai, aa ka whakawhiwhia kingaa mea kino wheenei i te huakita, hei tauira te Escherichia coli. Naateenei, ko te hangai o te kuuparuparutanga o te pua e kaha ake ai i ngaawaahi kii ana, i ngaa tahataha o te kooawa.

WhakakapingaKo ngaa tikanga hao o naaianei e haere tahi ai me te koorero pai o te kai, tae atu ki temate o roto i te kai moo te tangata. Ahakoa, ka hao i te tikanga tawhito he pai. Ko tetuumanako ko te tikanga hao o teenei kai e kite maarama mai ai e whakaheke iho ai temate ki te tangata i roto i te kai, aa, e ora anoo ai tenei momo kai moo ake tonu atu.

Fluorescent labelledE. coli 0157:H7 lurk inside lettuce.© Karl Matthews, Rutgers University

This project was funded by FRST under a Tuapapa Putaiao Maori Fellowship

Contact: Lorraine Dixonlorrainedixon@xtra.co.nz

O ngaa katonga 13 tawhito katoa,12 i pai, 1 i tino pai.

O ngaa katonga 14 o naaianei, e 9 ipai, e 5 kaare i pai, aa, kaare e taea ete tangata te kai.

Microbiological quality ofnon-traditional

harvested watercress

64.20%

35.80%

n = 5 n = 9

SatisfactoryUnacceptable

Microbiological quality oftraditional

harvested watercress

8.40%

91.60%

n = 12

n = 1 SatisfactoryMinimumstandard