WARNING - Tatmjolk!!

From: Loyd Wix (Loyd.Wix@unilever.com)
Date: Tue Feb 02 1999 - 05:05:55 PST

Date: 02 Feb 1999 13:05:55 Z
From: Loyd Wix <Loyd.Wix@unilever.com>
To: cp@opus.hpl.hp.com
Message-Id: <aabcdefg299$foo@default>
Subject: WARNING - Tatmjolk!!

          Dear All,
          I thought it was worth while putting down a few words of
          caution regarding the current list interest in fermented
          dairy products involving Pinguicula before some one ends up
          with food poisoning!
          Most milk for consumption these days is pasteurised to
          ensure the removal of any pathogenic bacteria from the milk.
          Prior to introduction of pasteurised milk, a whole host of
          diseases such as TB and food poisoning such as Salmonellosis
          were transmitted to people. Even now, each year many major
          outbreaks of food borne infection are attributed to non
          pasteurised milk. Thus contaminating milk with Pinguicula
          leaves does run the real risk of food poisoning - just think
          what may be attached to those leaves! Things will be made
          worse by storing the contaminated milk at elevated
          temperatures as milk is an excellent medium to grow
          pathogenic bacteria. So please be careful!!!
>set (or something like that - ask a chemist if you want a
>reliably scientific description of what happens.) It
>seemed worth giving it a go in the interest of science.
          OK I'm a Food Scientist (rather than a chemist) and my main
          interest is in ice cream but I do know a bit about such
          fermentation's. Pinguicula leaves have been used as a
          substitute Rennet to make cheese over much of their European
          range. The use in Scandinavia was to make these thick ropy
          fermented milk products. From what I understand from the
          literature most of the time a portion of an early batch of
          Tatmjolk was used to start a new batch. P.vulgaris leaves
          were used only when a previous batch was unobtainable or the
          milk was perceived as separating too quickly. Thus I believe
          we are talking about a bacterial fermentation rather
          anything enzymatic from the plants.
          Fresh (unpasteurised) milk contains many organisms which
          although not harmful will cause changes to the milk. These
          bacteria can consume the milk sugar lactose (many bacteria
          cannot utilise this sugar) and produce lactic acid as a by
          product. This causes the acidity of the milk to rise and
          when the pH gets to below pH5.2, one of the milk proteins
          (casein) starts to precipitate and comes out of solution.
          This can cause the milk to separate into the precipitated
          casein 'curds' and an aqueous phase of the whey proteins
          which are more pH stable. With Tatmjolk type products such a
          separation is undesirable though some ropy culture bacteria
          have the ability to produce starch type materials and in
          addition rather than forming single cells, these organisms
          form long chains or ropes of cells attached to one another.
          This has the effect of preventing separation of the
          acidified material (starch type materials are used to
          stabilise yoghurt drinks for similar reasons), as well as
          introducing the peculiar stringy texture to the material.
          Such bacterial starter cultures are now commercially
          available and are extremely safe and reasonably reliable to
          use - far less hit and miss compared to using Pinguicula
          Peters experience:
>Within 10-15 minutes it had curdled into long ropy strands
>and I figured was ready for consumption. Perhaps not
>surprisingly, it wasn't very nice - rather bitter and
>with a texture like toad spawn. Worse than sago, but then
>I've never been much of a fan of that sort of thing. I
>tried adding some sugar, but it didn't improve it much. I
>didn't finish it and wouldn't want to try it again. Even
>the cat wouldn't eat it!
          From what I remember Peter you used what was left in a
          carton of (pasteurised) milk getting close to its best
          before date. In which case from your description I do not
          believe you made true Tatmjolk. Pasteurisation also destroys
          the natural milk bacteria which cause the milk to go sour
          but in a non offensive manner. What tends to happen with
          pasteurised milk is the milk becomes the home for low
          temperature spoilage organisms whilst in the fridge such as
          Pseudomonad ssp - the same organisms which can make prawns
          glow in the dark. These organisms start to break down the
          milk proteins and fat and thus tend to make the the milk
          putrefy rather than going pleasantly sour. The bitterness
          you tasted would indicate this. Tatmjolk should be sour
          stringy but pleasant.
          Hope this is of interest

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