Food preservation workshop

Gabrielle Allen Senior Food Science OfficerDHHS Food Safety Unit

The good old days……

The history of preserving foods

Veal doorstops

Spot the preservative

Heat preserved foods

Spot the preservative

Refrigeration

Spot the preservative

Freezing

Spot the preservative

Reduction of pH

Spot the preservative

Reduced water activity

Spot the preservative

Salt

Spot the preservative

Additives

Spot the preservative

Processing aids

Spot the preservative

Irradiated

Spot the preservative

High-pressure processing

Spot the preservative

Packaging

Spot the preservative

Hurdle technology

saltsodium nitrateheat treatmentpackagingrefrigeration

Modified atmospheric packaging (MAP) and vacuum packaging

• Oxygen removed and flushed with gas (mix of nitrogen, oxygen and carbon dioxide).

• Typical areas of application:• potato chips and other snack foods

• retail ready fresh meats

• ready meals

• fresh produce

• processed meats and small goods

• bread and bakery products

• items as diverse as coffee, fresh pasta and cheese

Pros and cons

• MAP and vacuum delays:

• growth of some bacteria, yeasts and moulds

• rancidity

• preserves the smell, taste, texture and appearance

• enzymatic browning

• staling

• potential of botulism and other pathogens (listeria) due to anaerobic conditions, greater time and opportunity for outgrowth. Food poisoning before spoilage. Foods implicated such as, coleslaw, salad vegetables and smoked fish.

High-pressure processing (HPP)

• earliest HHP study was conducted in 1885

• more than 300 units of HPP equipment operate globally

• Approximately $1.50 - $3.00 per litre.

• typical areas of application• all kinds of meat products

• ready-to-eat meals

• vegetables

• sauces, marinades

• fruits, fruit juices and desserts

• dairy products

• processed fish and seafood

Pros and cons

• increased shelf life

• low-temperature preservation method

• food safety - inactivation of some foodborne pathogens

• additive-free preservation

• reduction in salt content

• results are independent of product size and geometry

• processing in final consumer packaging is possible (no recontamination)

• increases yield compared to traditional processes (e.g. extraction of lobster meat from the shell)

• pressure treatment alone, is not sufficient to inactivate spores of harmful pathogens such as Clostridium botulinum, hurdle technology required

Cheap and accessible for small businesses

Toll processing $1.50 - $3.00 per litre

Room temp Room temp Heat applied

Reduced pH Additives – Potassium sorbateAdditives – Sodium metabisulphite

Which preservation technique?

Sugar replacement SaltWater activity - sugar

Using the right preservative

References

1. The New Scientist 5 May 1960, the oldest canned food in the world? https://books.google.com.au/books?id=iKQy_w-eOAoC&pg=PA1139&lpg=PA1139&dq=.+A+4+lb+can+of+roasted+veal+manufactured+by+Donkin+and+Gamble,+1824.&source=bl&ots=9_XMX_d1S9&sig=khiWw_f4hB0tfLgprKpu69dmFVw&hl=en&sa=X&ved=0ahUKEwjbhfeyxYrWAhWBpJQKHfNeCNsQ6AEIJjAA#v=onepage&q&f=false

2. http://www.abc.net.au/news/2017-08-11/hundred-year-old-fruitcake-found/8799684

3. Castro-Ibáñez, M. I. Gil, A. Allende, Ready-to-eat vegetables: Current problems and potential solutions to reduce microbial risk in the production chain. LWT -Food Science & Technology 85, 284-292 (2017).

4. M. MikŠ-Krajnik et al., ENSURING FOOD SECURITY THROUGH ENHANCING MICROBIOLOGICAL FOOD SAFETY. COSMOS 11, 69-97 (2015).

5. J. H. Redmond, Choosing a Method for Quick Chilling or Freezing. Process Cooling 5, 10-13 (2017).

6. R. Sevenich, C. Rauh, D. Knorr, A scientific and interdisciplinary approach for high pressure processing as a future toolbox for safe and high quality products: A review.Innovative Food Science and Emerging Technologies 38, 65-75 (2016).

7. R. Sevenich, C. Rauh, D. Knorr, A scientific and interdisciplinary approach for high pressure processing as a future toolbox for safe and high quality products: A review.Innovative Food Science and Emerging Technologies 38, 65-75 (2016).

8. 6. T. Zipper, Food preservation explained. Chemistry in Australia, 20-25 (2013).

9. https://www.foodsafetymagazine.com/magazine-archive1/octobernovember-2003/opportunities-in-modified-atmosphere-packaging/?EMID=

10. https://www.food.gov.uk/sites/default/files/multimedia/pdfs/publication/vacpacguide.pdf

11. https://www.food.gov.uk/sites/default/files/multimedia/pdfs/publication/vacpack0708.pdf

12. The New Scientist 5 May 1960, the oldest canned food in the world? https://books.google.com.au/books?id=iKQy_w-eOAoC&pg=PA1139&lpg=PA1139&dq=.+A+4+lb+can+of+roasted+veal+manufactured+by+Donkin+and+Gamble,+1824.&source=bl&ots=9_XMX_d1S9&sig=khiWw_f4hB0tfLgprKpu69dmFVw&hl=en&sa=X&ved=0ahUKEwjbhfeyxYrWAhWBpJQKHfNeCNsQ6AEIJjAA#v=onepage&q&f=false