Yogurt Shelf-Life Extension

Hello!

 

I am working on a new fermented yogurt recipe.

 

The product has a 50 day shelf-life, and we are looking to extend it to 90 days.

 

What is the current industry standard for yogurt shelf-life?

 

What strategies can be applied to extend the current product shelf-life? Recipe reformulation, best industry packaging material, best industry packaging method, MAP, etc.?

 

Thanks!!!

Hi estherlev,

 

I presume that you are referring to re-pasteurised rather than fresh yogurt?

 

Kind regards,

 

Tony

 

Thank you for your reply.

This is actually a dairy free yogurt.

The base is pasteurized prior to fermentation.

What is the current industry standard for yogurt shelf-life?

What strategies can be applied to extend the current product shelf-life? Recipe reformulation, best industry packaging material, best industry packaging method, MAP, etc.?

Hi estherlev,

 

A fresh dairy yogurt has a typical shelf life ranging from 2 to 4 weeks.

 

Your shelf life seems excessive for a fresh fermented product but the formulation may be a factor. Also you may be filling aseptically which is ideal.

 

Yeasts & Moulds tend to be the main cause of shelf life restriction. The standard of your facility and filling machine can significantly affect the level of Y&M contamination.

 

There a few ways to tackle the problem of Y&M contamination:

 

Preservative such as potassium sorbate and/or inhibitors 

 

Re-pasteurise the fermented base and fill aseptically or hot fill to create an ambient stable yogurt. (Although this means there are not healthy or bio bacteria in the yogurt – sometimes I do wonder if long life yogurts should really be called yogurt :uhm: )

 

Up your hygiene standards, use HEPA filters to provide filtered air overpressure in incubation tanks, storage tanks and filling machines.

 

Kind regards,

 

Tony

Hi Tony,

Thanks for the response.

By fresh yogurt do you refer to yogurt that is made using pasteurized milk?

I've seen some yogurts in the market that have 60 days, perhaps more, especially Greek yogurt seems to have a longer shelf life compared to others.

Can you provide an industry benchmark on this?

Thank you.

Hi estherlev,

 

A fresh yogurt is typically made with a pasteurised milk base (although there are some made from raw milk, this is much higher risk). The pasteurised milk base is cooled to around 40 °C and the yogurt culture added. This is then allowed to ferment until it the pH drops to a target pH which is typically 4.5 or below.

This base is then cooled and packed and then cooled further to refrigeration temperature. This product contains live cultures and has a shelf life of a few weeks. Some fresh yogurts may have extended life due to increased hygiene and aseptic/ultra hygienic filling to prevent yeast & mould contamination.

 

For a long life yogurt the fermented based reaches the correct pH and is then re-pasteurised and packed on an aseptic filler or is hot filled to effectively pasteurise the product and kill any yeasts/mould contamination in the packaging. There are no live cultures in long life yogurts. Long life yogurts have a life of several months plus depending on the storage conditions and the quality of the packaging in preventing moisture loss.

 

Kind regards,

 

Tony

We're making non-dairy yogurts, shelf life is 42 days. We tried to extend it, but as Tony-C mentioned the main issue was Y&M (mold started growing after 42 days). We assumed, that happened because of plant base (coconut). RE: dairy yogurts, their shelf life could easily reach 65-70 days.

Thanks so much for your feedback.

For dairy yogurt as you mention, how can they easily reach 70 days? What strategies can be implemented (if any different than information Ttony kindly provided).

Pretty much same as Tony mentioned.

This is an extremely interesting topic. Have you considered doing a 3rd party shelf life study verifying your proposed shelf life extension? If so, would you be willing to share some info/data? 

 

 

 

I do agree with most people, Y/M after that first few weeks would be your main priority/pathogen of interest

Hello.

What's the name of your lab?

Yes, we already conducted a shelf life study, that's how we know the product is at 50 days shelf life.

Before doing another shelf life study, we want to implement strategies to further increase the shelf life.

Then, we could re-test to validate the new steps add more days to our current shelf life.

Tony-C,
Do you hace any experience or knowledge with MAP For yogurt type applications?
Any feedback you can provide would be appreciated.

Hi estherlev,

 

Aseptic filling is a type of modified atmosphere where air is filtered using HEPA filters to a high standard of clean air or the air sterilised by using hydrogen peroxide.

 

I have seen some claims* that Carbon Dioxide/Nitrogen will assist in shelf life extension but it does not seem to be anywhere near as effective as it is with hard cheese.

 

* In this example BOC claim a normal yoghurt shelf life of 10-14 days can be extended to 22-25 days. BOC Modified Atmosphere Packaging (MAP) in dairy food processing

 

Whilst this is important, packaging can be a major source of Y&M so that needs to be dealt with as well, which is why I have referred to aseptic packing and “hot fill” in my previous posts.

 

Kind regards,

 

Tony

is high pressure processing an option?   

 

(PDF) Fruit yogurt processed with high pressure (researchgate.net)

is high pressure processing an option?   

 

(PDF) Fruit yogurt processed with high pressure (researchgate.net)

 

An interesting idea kingstudruler1.

 

I am not sure how well the yogurt structure would stand up to HPP.

 

Also in an ideal world, the yogurt would be processed in the finished pack to prevent post-process contamination. I’m not sure a pot with sealed lid would stand up to that but a pouch may be an option.

 

I would be wanting to do some significant trials before investing in this process for yogurts.

 

Kind regards,

 

Tony

An interesting idea kingstudruler1.

 

I am not sure how well the yogurt structure would stand up to HPP.

 

Also in an ideal world, the yogurt would be processed in the finished pack to prevent post-process contamination. I’m not sure a pot with sealed lid would stand up to that but a pouch may be an option.

 

I would be wanting to do some significant trials before investing in this process for yogurts.

 

Kind regards,

 

Tony

yes its really expensive.  there are some companies that toll process (in package).   I am not sure what the packaging requirements are, but the last time I talked to someone regarding there process, I was surprised as to packaging diversity.  

Radiation.  You can push that shelf life out to the point that the packaging starts to break down.

 

We really don't use it as much as we should, considering how effective it is, but people are scared of cartoonish misconceptions.

Food irradiation is highly regulated and VERY cost prohibitive with the added bonus of having to ship your product to the facility and then bring it back for storage

 

Not sure they are cartoonish at all, seems to me the word prudent works better