BO QUN V CH BIN NNG SN BO QUN V CH BIN NNG SN

CNG NGH SAU THU HOCH CNG NGH SAU THU HOCH

MT S KHI NIM CHNH

Qu trnh sn xut ra lng thc, thc phm gm 2 giai on: trc thu hoch sau thu hoch (STH) Giai on cn thu hoch nm trong cc hot ng trc thu hoch nhng li nh hng trc tip n cht lng sn phm STH

GIAI ON TRC THU HOCHQuyt nh nng sut v cht lng nng sn

GIAI ON CN THU HOCHL giai on cy trng, vt nui c s bin i su sc v cht v lng. Nng sn s t hiu qu cao nu giai on ny c quan tm v x l tt

GIAI ON SAU THU HOCH Gm: thu hoch, s ch (tch ht, lm sch, lm kh, phn loi...), vn chuyn, bo qun, ch bin v tip th. L cu ni gia sn xut nng nghip vi ngi tiu dng L u ra cho nng sn. Cc cng ngh lin quan n nhng hot ng ny c gi chung l cng ngh sau thu hoch

VAI TR, C IM CA GIAI ON STH

Cng ngh c hiu l h thng cc cng c, cc phng tin v cc gii php bin i cc ngun lc thnh sn phm v dch v. Cng ngh gm:- Con ngi (k nng v trnh chuyn mn) - K thut (cc thng s k thut, b quyt v quytrnh cng ngh, )

- Thit b, my mc, cng c, v.v. - T chc qun l, thng tin

VAI TR, C IM CA GIAI ON STH Cng ngh sau thu hoch l h thng cc cng c, phng tin v gii php bin i cc loi nng sn th thnh cc sn phm phc v trc tip v gin tip cho nhu cu ca con ngi.

VAI TR CA CNG NGH STH i vi sn xut nng nghip L u ra cho nng sn, a nng sn n vi ngi tiu dng Gp phn n nh sn xut nng nghip Gp phn m rng th trng cho nng sn, n nh sn xut cho cng on trc thu hoch To nhiu sn phm mi c tnh cnh tranh cao Gp phn thc y s chuyn i ca sn xut nng nghip.

Cn pht trin mnh v s ch, bo qun v ch bin nng sn : Nng cao gi tr nng sn hng ho Chuyn dch c cu kinh t To vic lm cho ngi lao ng Tng thu nhp cho x hi Khc phc hin tng mt ma trong nh: Trc nhng nm 70, tn tht trong khu bo qun ti 20 34% do thiu phng tin v cng ngh bo qun Su hi, la, ng trong kho lm thit hi 1/5 1/3 tng sn lng nng sn

Tn tht trong bo qun lng thc mt s nc trc 1970(Theo s liu ca Chrisman Sititonga, Indonexia. Tp chi Change in Post Harvest Handling of Grain 1994)

Nc Nigeria n Malaxia Inonexia Thi lan Pakistan

Loi nng sn La nc Ng cc Go La Go La

T l tn tht (%) 34 20 17 12 21 10 8,8

Thi gian bo qun (thng) 24 12 9 12 9 6

Tn tht trong bo qun lng thc nhng nm 90

Nc

Loi nng sn

T l tn tht (%)

Ngun ti liu

Nigeria Trung Quc Indonexia Thi Lan Pakistan Vit Nam

Ng cc Ng cc La, ng La, ng La, ng La

2,1 6,7 3,6 5,0 5,0 3,5 5,2 3,2 3,7

A. Radnadan Ren Jong J. S. Davis J .S. Davis V.K. Baloch

1992 1992 1994 1994 1994

L Don Din 1994

MI LIN H GIA GIAI ON TRC THU HOCH V CNG NGH STH Giai on trc thu hoch: quyt nh nng sut c cht lng nng sn Phng thc canh tc tin tin: nng sn c cht lng cao, n nh Chn ging: ging mi c cht lng cao hn yu cu cng ngh sau thu hoch phi hot ng c hiu qu hn Ch ti tiu, bn phn: nh hng ln cht lng nng sn, cng nh vic bo qun Thi im thu hoch: nh hng ln n cht lng nng sn

TNH A DNG CA CNG NGH STH Gm cc khu: Cn thu hoch Thu hoch S ch (phn loi, lm sch, lm kh) Bo qun Ch bin Tip th

Bo qun v ch bin: 2 khu quan trng trong giai on sau thu hoch Cn quan tm y cc cng on: cn thu hoch, s ch, vn chuyn v c bit l tip th hng ho nng sn

Cn p dng nhiu loi hnh cng ngh khc nhau ph hp iu kin tng a phng:Cn thu hoch: cn quan tm k thut ti nh git, ti thm tit kim nc, m bo ng nhu cu sinh l ca cy. S ch: cn thit b tut, t, lm sch, phn loi, phn loi Ch bin: p dng cng ngh truyn thng (ct, gt, p, chit) v hin i (chin chn khng, gim p t ngt)

TNH A DNG CA NNG SN i tng: khng ng nht. Khu vc min Bc s dng trn 100 ging thc Trn 30 ging sn

u t cng ngh STH: Cn c nghin cu c bn gii quyt vn chung cho nng sn Nghin cu ng dng thch hp cho nhiu loi nng sn khc nhau.

TN THT STH V NGUYN NHN GY TN THT

TN THT STH Khi nim: mt mt, hao ph, thi hng, h hi. Tn tht sau thu hoch: tng tn tht thuc cc khu ca giai on sau thu hoch nh thu hoch, s ch, bo qun, vn chuyn, ch bin v maketing,

Tn tht STH bao gm: Tn tht s lng Tn tht cht lng Tn tht dinh dng Tn tht kinh t Tn tht x hi

- Tn tht s lng: mt mt v trng lng v c xc nh ch yu bng phng php cn, o. - Tn tht v cht lng nng sn c nh gi thng qua cc ch tiu: + dinh dng + v sinh an ton thc phm + cm quan

- Tn tht v kinh t: tng tn tht v s lng v cht lng c quy thnh tin hoc % gi tr ban u ca nng sn.

- Tn tht x hi: vn an ninh lng thc, an ton thc phm, mi trng sinh thi, to vic lm cho ngi lao ng

TN THT STH VIT NAM V TRN TH GII Trn th gii: Cuc "Cch mng xanh (1970-80) nng cao nng sut mt s cy trng chnh ln gp i. tng 10% nng sut cy trng trong nn nng nghip bn vng, con ngi phi u t rt ln v ca ci vt cht, ti nguyn thin nhin. Nhng tn tht 10%, thm ch 20% trong giai on STH li rt d xy ra v t c ch n.

Vit Nam Hn 15 nm i mi, cng ngh STH ca Vit Nam pht trin tt Nhiu cng ngh tin tin trong bo qun la, go, ng, rau qu, xay xt go, sy kh nng sn c p dng.

Tn tht trung bnh STH ca sn xut la Vit Nam(Theo s liu ca Tng cc thng k, Vin Cng ngh STH, L Don Din, 1994)

TT1 2 3 4 5 6

Cc khu sn xutThu hoch p, tut Sy kh, lm sch Vn chuyn Bo qun Xay xt Cng

Tn tht (%)1,3-1,7 1,4-1,8 1,9-2,1 1,2-1,5 3,2-3,9 (Dao ng ln gia cc khu vc) 4,0-5,0 13,0-16,0

Tn tht thc sau 6 thng bo qun thc vi cc phng tin khc nhau(S liu iu tra ca Vin CNSTH ti ngoi thnh H Ni 1994 1995) T l cc PTBao gai Quy ct Thng g Thng st Chum vi

Sinh (42,0%)* (23,0%) (15,0%) (11,5%) (8,5%) vt hi Chut 12,2 12,5 0 0 0 ph Su mt 11,6 11,8 5,2 2,6 2,5 Cng(*) T l h s dng phng tin bo qun

Tn tht trung bnh (%) 9,02 6,43 15,45

Tn tht thc sau 6 thng bo qun thc vi cc phng tin khc nhau(Theo kt qu iu tra 2001-2002 ti H ni) Phng tin bo qun Bao gai Sinh vt hi Su mt 4,0 Quy ct Thng phi Thng tn Chum vi Tn tht TB

(8,78%) (1,13%) (34,39%) (47,6%) (8,10%) 3,2 2,7 1,2 2,8

Tn tht sau thu hoch trung bnh cc tnh pha Bc i vi rau qu l 20-25%, sn 21%, khoai lang 18%.(Theo iu tra ca Hi lm vn Vit Nam nm 1996)

TN THT TRONG SN XUT LA, GO

Tn tht khi thu hochGm: gt b st, thc ri khi gt, khi vn chuyn t ch ny n ch khc trn rung, thc li rung ch phi, ch vn chuyn, do chim, chut n

Tn tht khi p, tut laBao gm: nhng ht b bay khi vng tut; nhng ht b dp hoc nt; t l thu hi go nguyn do go b v, dp hoc nt ngm khi tut

Tn tht khi lm khDo chim chut v ng vt khc n khi phi Do gi cun cc ht thc i Do phi khng ng k thut ht b rn, nt t gim t l go thu hi

Tn tht trong qu trnh lm sch, phn loiTn tht do thc bay trong qu trnh lm sch phn loi. Ngay c ht chc, ht lng, ht non b loi theo ph phm cng c tnh trong khu ny.

Tn tht trong qu trnh vn chuynThc b ri dc ng Thc b t do ma trong qu trnh vn chuyn

Tn tht trong bo qun Do su, mt, chut, chim ., n hoc ph hi Do nm, vi sinh vt ph hi (chua, kt bnh)

Tn tht trong xay xt Gim t l thu hi go Gim cht lng go xay xt nn gi thnh ca go cng b gim

MT S NGUYN NHN CHNH GY TN THT STH

Thng thng trong 24 gi , 1 tn rau, c, qu gim 0,6 0,8 kg trng lng, trong 75 85% l do mt nc, cn 15 23% l tn tht cht kh do qu trnh h hp. S gim khi lng do bay hi nc v tiu tn cht kh do h hp gi l s gim khi lng t nhin.

Nguyn nhn gy tn tht STH do t bn ngoi tc ng vo Mi trng, kh hu: Trong iu kin phng tin bo qun khng tt, mi trng bn ngoi tc ng n tn tht trong bo qun. m tng i ca khng kh: trong mi trng bo qun nh hng n tc bay hi nc ca nng sn. m mi trng cng thp, tc bay hi nc cng cao; rau, c, qu ti b ho.

Nhit khng kh: l yu t quan trng gp phn gy tn tht trong bo qun. Nhit tng, lm tng cc phn ng sinh ho trong nng sn. Tuy nhin, phm vi tng nhit cng ch c hn. Nhit vt qu 250C - 300C s dn n cng h hp gim khi nhit tng.

Sinh vt hi C 4 nhm chnh: + Vi sinh vt (Nm men, nm mc, vi khun ) + Cn trng, su b + Loi gm nhm (chut, sc) + Chim, di

Cc sinh vt gy hi cho nng sn nh: n nng sn thc phm Lm nhim bn nng sn thc phm do sinh vt hi thi phn hoc xc cht, lm vn cc, lm cho nng sn thc phm c mi l kh chu, lm tng tp cht v thay i thnh phn dinh dng ca NSTP.

Thi ra mt lng nhit, m lm sn phm bc nng, thc y s pht trin ca vi sinh vt ph hi nng sn. a vo nng sn thc phm nhiu c t, mm bnh. Th d, c t afflatoxin t nm mc, bnh dch hch, bnh t t chut , mn nga t mt

Tc ng gy hi ca vi sinh vt: Lm thay i mu sc nng sn thc phm Lm mt mi thm t nhin ca NSTP Lm thay i cu trc NSTP Lm bin i thnh phn dinh dng Lm mi trng nui dng vi sinh vt gy bnh

Mt s mt in hnh:

Mt c thn (Rhizothertha dominica F.)

* C chiu di t 2-3mm, thuc B cnh cng, chng n la, ng, cao lng, sn, la m v nhiu loi thc phm khc. Chu k sng: 7-30 ngy, mi lm 500 trng.

Mt go (Sitophilus oryzae L)

C vi di, chiu di 33,5mm, n ht ng cc, khoai sn lt kh, m si. Chu k sng: 12-32 ngy. Mi ln 600 trng, vo ht nng sn.

Mt bt (Tribolium castaneum Herbst)

Di 3-3,5mm, n ng cc, bt ng cc, bnh kh... Chu k vng i 40-45 ngy, c th sng 2 nm, chu nhit cao 50C. mi ln 400 trng.

Ngi bt (Ephestia kuchniella Zell)

Thn di 7-14mm, si cnh 20-25mm, thuc B cnh vy, chng n bt, cm, thc n gia sc, bnh m kh, su n nhiu loi lng thc, thc phm nh bt, u lc, bnh ko... chu k sng 4045 ngy, 1 nm c 4 th h. 200-300 trng. Sau 6-12 ngy thnh su, su chui vo ng nng sn ph hoi.

Mt bt (Tyroglypus farnae L.)

Chiu

di

0,4-0,7mm, pht

thuc lp nhn,

trin tt trn nng sn c m cao trn 14%. trng vo trong ht, lm cho ht b hi, ng. Chu k th h 1416 ngy, mi ln 200 trng.

Tc ng ca loi gm nhm chim, di...

Ch yu l chut v chng c kh nng sinh sn rt ln.

Mt s loi chut chnh Vit nam : Chut ng ln, chut ng nh, chut cng, chut n, chut nht nh

Tc ng ca con ngi Con ngi ng vai tr quyt nh n cht lng bo qun cng nh tn tht STH ca nng sn. Thng qua cc yu t cng ngh, cc phng tin bo qun, con ngi c th qun l c cc yu t dn n tn tht STH. S thiu hiu bit, km thc trch nhim s dn n nhng tn tht rt ln v s lngv cht lng nng sn thc phm.

Cc yu t gim tn tht STH : Phng tin bo qun thch hp Cng ngh bo qun thch ng vi mi loi NSTP Cht bo qun c hiu qu cao, t c hi vi ngi v mi trng sinh thi Chnh sch qun l cht ch, chng ly nhim sinh vt hi trong bo qun, h tr p dng cng ngh mi

NH HNG CA TN THT SAU THU HOCH N SN XUT NNG NGHIP V KINH T X HI

Tn tht STH nh hng n kinh t h nng dn

S tn tht v s lng hay cht lng nng sn sau thu hoch u nh hng trc tip n thu nhp ca mi h nng dn.

Tn tht STH xy ra nhiu khu, trong c khu gn vi hot ng ca nng dn. Tn tht trong cc khu: thu hoch, s ch (lm sch, phi sy), phn loi, vn chuyn ni b, bo qun ti h ... s tc ng trc tip n kinh t h nng dn. Tn tht trong nhng khu khc trong giai on STH nh: bo qun ti kho tp trung, vn chuyn ra khi vng sn xut, ch bin th lin quan n cc nh doanh nghip hay nh sn xut.

Tn tht STH nh hng sn xut Nng nghip Vic thay th cng ngh bo qun, x l STH bi cc loi ha cht bng cc bin php khc gim ng k nguy c nhim mi trng, nguy c nh hng n sc kho ngi tiu dng. Vic p dng cc cng ngh mi trong s ch, ch bin v tip th gip cho nng sn c cht lng cao, n nh gp phn gi vng th trng tiu th.

CC PHNG PHP GIM TN THT STH

Nghin cu pht trin v p dng cng ngh thit b hin i Gn bo qun, ch bin nng sn vi sn xut nng nghip o to chuyn mn v giai on STH cho ngi sn xut v ngi qun l Tng cng s quan tm ca Nh nc

Cc bin php k thut trong bo qun Bo qun trong kho thng: kho kin c, bn kin c, kho n gin, kho ngoi ng, hm t Bo qun trong kho c iu tit vi kh hu: kho lnh, kho mt, kho c mi trng kh iu bin (Modified atmosphere, MA) Bo qun bng cht bo qun: mui n, axit hu c, khng sinh, ho cht BVTV, ozon, ion, kh tr Bo qun nng sn bng cc tc nhn vt l (nhit nng, lnh, lm kh, tia gamma, tia cc tm, sng siu m....) Ch bin bo qun nh: ng hp, l, ln men, hun khi. Ci to cc ging c kh nng phng chng su bnh tt.

QUI TRNH BO QUN THC GO, NG QUI M H

Thu hoch Phn loi Tut (t) Lm kh Lm sch Lm ngui k v x l khi cn Tiu th Bo qun trong cc phng tin Kim tra nh

XIN CM N