{"product_id":"standard-methods-agar-for-enumeration-of-bacteria-500-g-acumedia-7157a","title":"XLT4 Agar for Enumeration of Bacteria, 500 g, Acumedia 7157A","description":"\u003cp\u003e\u003cstrong\u003eAcumedia® XLT4 Agar for Enumeration of Bacteria, 500 g, 7157A\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eFeatures:\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eXLT4 Agar is used with Tergitol 4 for isolation of non-typhi Salmonella spp and is not intended for use in diagnosis of disease or other conditions in humans\u003c\/li\u003e\n\u003cli\u003eSelective differential isolation medium for specific detection of Salmonella spp. from environmental and food samples\u003c\/li\u003e\n\u003cli\u003eDue to its highly selective nature, XLT4 Agar is particularly effective when used with samples where overgrowth of contaminating flora is expected, for example, fecally contaminated agricultural samples\u003c\/li\u003e\n\u003cli\u003eDeveloped to perform as per Miller \u0026amp; Tate in 1990, this medium was found to improve recovery of non-typhi Salmonella from chicken and farm environmental samples\u003c\/li\u003e\n\u003cli\u003eDusch and Altwegg further established application of XLT4 Agar to salmonellae detection in clinical samples, with notable exceptions of Salmonella typhi and Salmonella paratyphi\u003c\/li\u003e\n\u003cli\u003ePresence of peptone and yeast extract provides sufficient nutrients to allow optimal growth of Salmonella spp.\u003c\/li\u003e\n\u003cli\u003eSelectivity is provided by anionic surfactant Niaproof® 4 (formerly known as Tergitol-4 \/ sodium tetradecylsulfate) — compound acts as effective selective agent which is active against Grampositive and many Gram-negative organisms, including Proteus spp.\u003c\/li\u003e\n\u003cli\u003eDifferentiation is based on fermentation of sugars xylose, lactose and sucrose in addition to decarboxylation of lysine\u003c\/li\u003e\n\u003cli\u003eInclusion of pH indicator, phenol red, provides visual evidence of pH decrease (yellow) or increase (red) in medium\u003c\/li\u003e\n\u003cli\u003eAmmonium iron (III) citrate is present to distinguish hydrogen-sulfide (H2S) producing from non-H2S producing organisms\u003c\/li\u003e\n\u003cli\u003eMost enteric organisms, except Shigella, will ferment xylose to produce acid\u003c\/li\u003e\n\u003cli\u003eHowever, salmonellae will also decarboxylate lysine to keep  pH neutral to alkali, thus maintaining red coloration\u003c\/li\u003e\n\u003cli\u003eAt near neutral pH, Salmonella can produce H\u003csub\u003e2\u003c\/sub\u003eS from reduction of ammonium iron (III) citrate and thiosulphate ions producing black or black-centered colonies\u003c\/li\u003e\n\u003cli\u003eNon H\u003csub\u003e2\u003c\/sub\u003eS-producing salmonellae will be red without black center\u003c\/li\u003e\n\u003cli\u003eOther Enterobacteriaceae (non-salmonellae) which are not inhibited by Niaproof-4, will ferment xylose, lactose and\/or sucrose but will not decarboxylate lysine — this fermentation activity causes decrease in pH, resulting in color change within colonies from red to yellow\u003c\/li\u003e\n\u003cli\u003eAppearance: beige pink powder\u003c\/li\u003e\n\u003cli\u003epH: 7.2-7.6\u003c\/li\u003e\n\u003cli\u003eFlammability (gas, solid): non-flammable\u003c\/li\u003e\n\u003cli\u003eSolubility: soluble in water\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Others","offers":[{"title":"EA (1)","offer_id":51110773915963,"sku":"60-7157A-EA","price":108.9,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0921\/2041\/6571\/files\/60-7157A.png?v=1784700957","url":"https:\/\/preiser.com\/products\/standard-methods-agar-for-enumeration-of-bacteria-500-g-acumedia-7157a","provider":"Preiser Scientific","version":"1.0","type":"link"}