Is there anything worse than when you carefully craft a sandwich, stack it high on your favourite bread, only to bite into it and taste a fuzzy, green patch of mould?


Thanks to University of Alberta researchers, a mouth full of mouldy bread may soon be a thing of the past.


The scientists have discovered what makes sourdough bread typically resistant to mould and may be able to apply the science to other varieties of bread and other foods.


“Our research potentially provides a very useful tool to the food industry," Michael Gaenzle, a professor of Agricultural, Food & Nutritional Science at the University of Alberta, told Fast Company.


Sourdough bread has a longer shelf life because of an extra fermentation step not usually given to other types of bread. The fermentation of lactobacilli bacteria converts linoleic acid to hydroxy fatty acids -- which are great at resisting fungus.



Story continues after the slideshow





  • Ketchup


    Ketchup will maintain its quality for six months in the fridge. It's still safe to eat after this date (unless it has developed an off odor or mold appears).

    Photo by <a href="http://www.flickr.com/photos/doobybrain/213828192/sizes/l/in/photostream/" target="_hplink">Flickr: doobybrain</a>.




  • Olive OIl


    Olive oil can stay fresh for 18-24 months either in or out of the fridge. It is recommended that you keep it in a cool dark place -- and refrigeration is suggested if you live in warm climates. Most times, you will have long finished the oil before it comes even close to perishing.

    Photo from <a href="http://www.flickr.com/photos/bhamsandwich/4665992253/sizes/l/in/photostream/" target="_hplink">Flickr: bhamsandwich</a>.




  • Eggs, Raw In The Shell


    Eggs stay good for 3-5 weeks in the refrigerator and up to one year in the freezer (note: it's not recommended to freeze them in their shell). Eggs will normally keep long past the sell-by date; but to ensure that they last as long as possible avoid storing them in the refrigerator door -- the coolest part of the fridge is best.

    Photo from <a href="http://www.flickr.com/photos/ambernectar/3803765911/sizes/l/in/photostream/" target="_hplink">Flickr: Ambernectar 13</a>.




  • Milk, Pasteurized


    Milk will stay good one week past the sell by date, and three months in the freezer. But of course, if milk has developed on off odor or flavor, it's best to discard it.

    Photo from <a href="http://www.flickr.com/photos/loop_oh/3030317020/sizes/o/in/photostream/" target="_hplink">Flickr: loop_oh</a>.




  • Yogurt


    You have a 7-10 day window after the sell by date to enjoy your yogurt, (and one to two months if stored in the freezer.) But if mold appears, discard the yogurt. And if it was frozen, it's best to thaw it in the fridge.

    Photo from <a href="http://www.flickr.com/photos/lovemaegan/4483171610/sizes/o/in/photostream/" target="_hplink">Flickr: ...love Maegan</a>.




  • Mayonnaise


    Don't throw it out just yet! An open jar of refrigerated mayonnaise is safe and good for consumption up to 2-3 months after the marked expiration date. And even then, the product may still be safe to eat, it just might begin to change in terms of texture and color.

    Photo from <a href="http://www.flickr.com/photos/clango/487259906/sizes/l/in/photostream/" target="_hplink">Flickr: clango</a>.




  • Peanut Butter


    An open jar of peanut butter will remain fresh up to three months in the pantry. After that point, it's recommended to store the peanut butter in the fridge (where it can maintain its quality for another 3-4 months). If you don't refrigerate, oil separation may occur.

    Photo from <a href="http://www.flickr.com/photos/cantoni/6398248857/sizes/l/in/photostream/" target="_hplink">Flickr: brianc</a>.




  • Pickles


    Pickles, once opened, stay good for a whole year in the refrigerator. So if you've just come across a jar in your fridge, chances are, they're still delicious. Same goes for brine-packed jars of olives and capers.

    Photo from <a href="http://www.flickr.com/photos/ejchang/4823204395/sizes/l/in/photostream/" target="_hplink">Flickr: sleepyneko</a>.




  • Soy Milk


    Despite what you might think, soy milk has a similar self life to regular milk. It lasts about 7-10 days after the date indicated on the carton.

    Photo from <a href="http://www.flickr.com/photos/theimpulsivebuy/5180297645/sizes/l/in/photostream/" target="_hplink">Flickr: theimpulsivebuy</a>.




  • Sour Cream


    Sour cream is a tough food item to judge, since it's supposed to have a slightly soured taste. It can keep two weeks, tightly covered, in the fridge. And unlike most other dairy products, it doesn't freeze well.

    Photo from <a href="http://www.flickr.com/photos/mogula/6987170303/sizes/l/in/photostream/" target="_hplink">Flickr: limin_chiu</a>.




  • Vinegar


    The shelf-life of vinegar is almost indefinite <a href="http://www.versatilevinegar.org/faqs.html">according to versatilevinegar.com</a>. Aesthetic changes such as color or the development of sediment may occur in non-white vinegars over time, but the product is still safe to use. Photo from <a href="http://www.flickr.com/photos/felishumanus/484150776/sizes/o/in/photostream">Flickr: felishmanus</a>




  • Honey


    Even more so than vinegar, honey's quality remains unchanged over time. The low water content and high acidic level makes the food an unfavorable breeding ground for bacteria, in spite of its sugary nature. Photo from <a href="http://www.flickr.com/photos/cygnus921/3712930982/sizes/l/in/photostream/">Flickr: cygnus921</a>




  • Mustard


    When purchased at a store, mustard lasts anywhere from one to two years past its expiration date. This variation is due to differing storage methods -- when left unopened in the pantry, mustard lasts an extra year. Homemade mustard doesn't have the same shelf life, and expires much more quickly. Photo from <a href="http://www.flickr.com/photos/lifeontheedge/2316757256/sizes/l/in/photostream/">Flickr: Marshall Astor - Food Fetishist</a>




  • Almond Milk


    Just like milk and soy milk, almost milk lasts 7-10 days past its printed date, unless it's stored unopened in the pantry, in which case this beverage can stay good up to a month after. <strong>Photo from <a href="http://www.flickr.com/photos/aarongustafson/123422518/sizes/m/in/photostream/">Flickr: Aaron Gustafson</a></strong>




  • Whipped Cream


    Canned whipped cream can last up to three months past its printed date, whereas Cool Whip only lasts about 7-10 days. Photo from <a href="http://www.flickr.com/photos/stevendepolo/5159788513/sizes/l/in/photostream/">Flickr: stevedepolo</a>




  • Butter


    Plain ol' butter lasts about 2 weeks after its expiration date; Butter with olive oil lasts about a week more than that. Stick butter in the freezer and it can last up to 9 months longer. Photo from <a href="http://www.flickr.com/photos/sionakaren/3871517484/sizes/l/in/photostream/">Flickr: Siona Karen</a>




  • Half and Half


    Once opened, half and half, and all other liquid creams, last about 5-7 days after their expiration date. Photo by <a href="http://www.flickr.com/photos/greencolander/1463911167/sizes/l/in/photostream/">Flickr: Greencolander</a>




  • Coffee


    An open container of ground coffee will last 3 to 5 months past the best before date, whereas coffee beans will last up to 6 months. Photo from <a href="http://www.flickr.com/photos/epsos/8097327748/sizes/l/in/photostream/">Flickr: EpSos.de</a>




  • Pasta


    Dry pasta may seem to have an infinite shelf life. It doesn't, but it has quite a long one -- It'll last 1-2 years past the best before date. Photo from <a href="http://www.flickr.com/photos/duncan_h/4201489578/sizes/l/in/photostream/">Flickr: Duncan H</a>




  • Deli meat


    Packaged lunch meats last about 7-10 days longer than the best by date, whereas fresh meats will last around 5-6 days. Salami and pepperoni last much longer -- around 2-3 weeks. Photo from <a href="http://www.flickr.com/photos/stuart_spivack/67351962/sizes/l/in/photostream/">Flickr: stu_spivack</a>




  • Syrup


    Syrup may get thicker or darker when it gets older -- it may even crystalize. But it is never technically "spoiled." Photo from <a href="http://www.flickr.com/photos/26085795@N02/4173693000/sizes/l/in/photostream/">Flickr: jemasmith</a>




  • Tea


    Whether your tea leaves are packaged or loose, they'll last anywhere from 6 months to a year past their expiration date. Photo from <a href="http://www.flickr.com/photos/tenderisthebridge/269425312/sizes/l/in/photostream/">Flickr: Scout Seventeen</a>




  • Spices


    With the exception of mint, which has a slightly shorter shelf life, most spices from cinnamon to cayenne pepper last 2-3 years past their expiration date. Photo from <a href="http://www.flickr.com/photos/crobj/5519129659/sizes/z/in/photostream/">Flickr: srqpix</a>







By collecting special sourdough bacteria, there's a chance to make bread that's not only mould-resistant, but also a product that tastes better.


"Preservatives can be eliminated from the recipes, and because sourdough bread has a more distinct and richer flavor compared to bread produced with yeast only," Gaenzle told webindia123.com.


The findings also have the potential to help protect crops, E! Science News reports.


According to Fast Company, the Natural Resources Defense Council estimates that grocery stores in the United States threw away 43 billion pounds of food in 2008, most of it being perishable, like bread.


Researchers south of the border are also trying to come up with a solution to bread gone bad. Texas company MicroZap claims to have created bread that has a shelf life of more than two months.


According to Business Insider, the bread is placed in a chamber and blasted with microwaves, which keep mould spores from forming for 60 days.


The company says their method also had the potential to kill salmonella without affecting quality, freshness or taste.


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