(1)滅菌不徹底:培養料滅菌不徹底會造成雜菌汙染,一般3-5天即可出現汙染現象。而滅菌不徹底也是由於下列幾個原因引起的:
①黴菌操作不當:一般雜菌的菌絲體與孢子經過常壓100℃、6-8小時或121℃、0.5-2小時均能殺死。目前食用菌培養料往往采用常壓滅菌法或高壓滅菌法。常壓滅菌對穀粒、糞草等材料的滅菌難度較大,不容易完全達到滅菌的效果;ergaoyamiejunfaxiaoguozeyaohaodeduo。caiyonggaoyamiejunshi,guanjianshibaguoneilengkongqipaijin,fouze,guoneibunengdadaobaohedezhengqiya,miejundewenduyedabudaoyaoqiu。caiyongchangyamiejunshi,miejuncangdezhouweizuihaoqichengyuanxing,yibianzaoneishengwenjunyun,zaodingqichengyuangongxing,zheyanglengningshuiyansibixialiuerbuhuidashijunzhongping(袋)。另外蒸汽不足、溫度不高等也是常壓滅菌不徹底的因素。
②培養料性質的影響:製種所需材料的種類、培養料中的含菌量、含(han)水(shui)量(liang)以(yi)及(ji)酸(suan)堿(jian)度(du)等(deng)都(dou)能(neng)影(ying)響(xiang)滅(mie)菌(jun)效(xiao)果(guo)。滅(mie)菌(jun)時(shi),要(yao)根(gen)據(ju)培(pei)養(yang)料(liao)配(pei)方(fang)的(de)不(bu)同(tong),選(xuan)擇(ze)相(xiang)應(ying)的(de)滅(mie)菌(jun)時(shi)間(jian)。選(xuan)用(yong)的(de)培(pei)養(yang)料(liao)一(yi)定(ding)要(yao)新(xin)鮮(xian)無(wu)黴(mei)變(bian)。從(cong)培(pei)養(yang)料(liao)滅(mie)菌(jun)前(qian)微(wei)生(sheng)物(wu)含(han)量(liang)來(lai)看(kan),微(wei)生(sheng)物(wu)數(shu)量(liang)越(yue)高(gao)則(ze)滅(mie)菌(jun)時(shi)間(jian)越(yue)長(chang),反(fan)之(zhi)則(ze)短(duan),所(suo)以(yi)培(pei)養(yang)料(liao)配(pei)製(zhi)完(wan)畢(bi)後(hou)必(bi)須(xu)及(ji)時(shi)滅(mie)菌(jun),裝(zhuang)袋(dai)後(hou)的(de)菌(jun)種(zhong)千(qian)萬(wan)不(bu)要(yao)過(guo)夜(ye)後(hou)再(zai)上(shang)鍋(guo)滅(mie)菌(jun),以(yi)免(mian)微(wei)生(sheng)物(wu)大(da)量(liang)繁(fan)殖(zhi),導(dao)致(zhi)料(liao)內(nei)的(de)含(han)菌(jun)量(liang)升(sheng)高(gao),並(bing)且(qie)會(hui)造(zao)成(cheng)料(liao)中(zhong)營(ying)養(yang)損(sun)失(shi)。水(shui)的(de)熱(re)傳(chuan)導(dao)性(xing)能(neng)比(bi)木(mu)屑(xie)、糞草等固體要強,如果培養料內水分均勻適宜,則滅菌效果好。培養料中應避免出現"夾心料"(即培養料中含有未吸水的幹料)。滅mie菌jun鍋guo內nei的de蒸zheng汽qi對dui夾jia心xin料liao的de穿chuan透tou能neng力li較jiao弱ruo,容rong易yi出chu現xian滅mie菌jun死si角jiao,達da不bu到dao滅mie菌jun的de目mu的de。另ling外wai,培pei養yang料liao的de酸suan堿jian度du也ye影ying響xiang滅mie菌jun的de效xiao果guo,偏pian酸suan的de培pei養yang料liao比bi中zhong性xing和he偏pian堿jian性xing的de滅mie菌jun時shi間jian要yao短duan。
③菌種瓶(袋)堆放不當:菌種瓶(袋)在zai滅mie菌jun鍋guo內nei的de堆dui放fang形xing式shi可ke影ying響xiang滅mie菌jun的de效xiao果guo。在zai排pai放fang時shi要yao留liu有you一yi定ding的de空kong隙xi,以yi便bian蒸zheng汽qi的de流liu通tong和he升sheng溫wen。對dui菌jun種zhong袋dai裝zhuang的de培pei養yang料liao滅mie菌jun時shi,由you於yu塑su料liao袋dai受shou熱re後hou容rong易yi變bian形xing變bian軟ruan,如ru裝zhuang料liao不bu緊jin,疊die壓ya堆dui放fang時shi則ze菌jun袋dai之zhi間jian的de空kong隙xi會hui減jian少shao,影ying響xiang滅mie菌jun的de效xiao果guo。
④菌種瓶或菌種袋的影響:製zhi種zhong時shi一yi般ban選xuan擇ze菌jun種zhong瓶ping或huo菌jun種zhong袋dai。塑su料liao袋dai傳chuan熱re速su度du快kuai,而er玻bo璃li瓶ping則ze傳chuan熱re速su度du慢man,在zai相xiang同tong培pei養yang料liao,使shi用yong相xiang同tong的de滅mie菌jun方fang法fa時shi,瓶ping裝zhuang料liao要yao比bi袋dai裝zhuang料liao滅mie菌jun時shi間jian稍shao長chang一yi些xie。另ling外wai,個ge別bie容rong器qi密mi封feng不bu嚴yan或huo細xi小xiao破po損sun,也ye可ke以yi導dao致zhi雜za菌jun的de汙wu染ran。
(2)接種操作不規範:食用菌接種過程需要嚴格的無菌操作,如操作不規範則極易造成培養料的雜菌汙染。汙染的雜菌一般是接種室空氣中雜菌、jundaibiaomiandezajunyijijiezhongrenyuandetibiaozajundeng。caozuobuguifanyinqipeiyangliaowurandetedian,shizajunzaipeiyangliaobiaomianshengchang,yibanfashengzaijundaikaikouchuyijijiezhongchu。yincibixuyaoyangezunshouwujuncaozuoguicheng,jiezhongshiyaoyong"菌室專用消毒王"進行嚴格的消毒處理。
(3)菌種帶雜菌:用(yong)於(yu)擴(kuo)大(da)培(pei)養(yang)的(de)原(yuan)種(zhong)本(ben)身(shen)必(bi)須(xu)是(shi)純(chun)菌(jun),這(zhe)樣(yang)才(cai)能(neng)保(bao)證(zheng)菌(jun)種(zhong)的(de)單(dan)一(yi)性(xing)。如(ru)果(guo)菌(jun)種(zhong)本(ben)身(shen)不(bu)純(chun),可(ke)造(zao)成(cheng)批(pi)量(liang)汙(wu)染(ran),生(sheng)產(chan)中(zhong)的(de)一(yi)批(pi)菌(jun)種(zhong)中(zhong),集(ji)中(zhong)在(zai)一(yi)起(qi)的(de)菌(jun)種(zhong)都(dou)出(chu)現(xian)汙(wu)染(ran),而(er)且(qie)汙(wu)染(ran)的(de)部(bu)位(wei)在(zai)菌(jun)種(zhong)塊(kuai)處(chu),汙(wu)染(ran)出(chu)現(xian)較(jiao)早(zao),接(jie)種(zhong)3-5天即可出現。因此我們在製種時應盡量采用生活力強、菌齡適宜、抗逆性強的優良菌種原種。
(4)培養室不潔淨:培養料不潔淨、空氣不流通、室(shi)內(nei)潮(chao)濕(shi),也(ye)可(ke)感(gan)染(ran)雜(za)菌(jun)。這(zhe)種(zhong)情(qing)況(kuang)下(xia)汙(wu)染(ran)率(lv)相(xiang)對(dui)較(jiao)低(di),但(dan)隨(sui)著(zhe)培(pei)養(yang)時(shi)間(jian)的(de)延(yan)長(chang),汙(wu)染(ran)率(lv)會(hui)逐(zhu)漸(jian)增(zeng)加(jia)。大(da)量(liang)汙(wu)染(ran)出(chu)現(xian)比(bi)較(jiao)晚(wan),一(yi)般(ban)在(zai)接(jie)種(zhong)10天後出現。
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