1 / 9

Dairy Industries: Milk Processing and Environmental Impact

Explore the biotechnological processes involved in milk treatment and production of products like yogurt and cheese. Learn about the environmental impact of dairy industry waste and how it can be mitigated. Understand the importance of aseptic conditions in working with micro-organisms.

williegreen
Download Presentation

Dairy Industries: Milk Processing and Environmental Impact

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Biotechnological Industries Unit 2

  2. Dairy Industries Chapter 5

  3. Milk • Normal milk contains sugar, fat, protein, vitamins & minerals • Sugar – provides energy • Fats – energy & insulation • Proteins – growth & repair • Vitamins – protect from deficiency diseases • Minerals – helps bones, blood, teeth, skin

  4. Milk treatment • Can be treated/processed: • a) removal of fat (skimmed/semi-skimmed) • b) heat treatment • - pasteurisation (72oC for 15 secs, then cooled) • - UHT (138oC for 2-5 secs) • - both help prevent bacterial growth • - Resauzarin dye test for presence of bacteria (purple – white) • c) evaporation (condensed) – milk heated to reduce water content

  5. Yoghurt • Produced from milk • Yoghurt-forming bacteria added to heat treated milk • Bacteria change sugar into lactic acid • - this ‘clots’ & ‘thickens’ the milk • Yoghurt is therefore tangy, acidic & slightly sour • Most bacteria can’t grow in these acid conditions • – natural preservative • ‘Natural’ & ‘Bio’ yoghurts contain live bacteria

  6. Yoghurt production

  7. Cheese • A solid food made from a liquid (milk) • Milk needs to curdle first • - cheese making bacteria are added • - they change sugar into lactic acid • Rennet is added to help the milk to curdle • - milk changed into curds (solid) & whey (liquid) • - acid clots the milk proteins into curds • Curds are chopped and mixed with salt • - cheese left to mature & develop flavour • Whey can be re-used as part of cattle feed

  8. Environmental Impact • In the past whey was disposed of as waste • Often poured into rivers/lakes • But, whey is rich in protein • So bacteria in rivers fed on the whey • More bacteria led to other species dying • - due to a lack of oxygen • Upgrading • Whey is now used as a feed for yeast • Also used for pig food • Whey powder used in many human foods

  9. Aseptic Conditions • When working with micro-organisms, conditions must be sterile or aseptic • - prevents experiment being contaminated • - prevents micro-organisms escaping from experiment • The following conditions should be used: • - no eating or drinking • - using protective clothing • - washing hands • - suitable work surfaces (glass/plastic) • - sterilised equipment (e.g. autoclave) • - a sterile inoculating loop to transfer microbes

More Related