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About Jim Pfister
Expertise
Food Engineering/Manufacturing, Food Packaging/Distribution, Engineering Beverage Lines, Reducing operating cost of packaging lines while increasing efficiency. Lean Manufacturing. Incorporating new package technology into existing operations. Training staff to achieve smooth transition from "start-up" to full production. Managing complex projects across multi-disciplinary lines. Equipment PreShipment Factory Acceptance testing and Commissioning programs for new equipment.

Experience
Employment history: Over thirty-five years of experience. Managed as much as $40MM in concurrent, multi-disciplinary projects, both domestic and international, and have worked with such firms as Campbell Soup, Coca-Cola, Hershey`s, and Nabisco.

Organizations: An author and speaker, as well as a member of the IoPP. Past Chairman of IoPP`s Consultant`s Council and Member of the Packaging Equipment Performance Committee.

Publications: PMMI Solutions `99, Monthly Packaging Tipsheets

You are here: Experts > Industry > Food Engineering > Food Engineering/Manufacturing > How to increase shelf life of product

Food Engineering/Manufacturing - How to increase shelf life of product

Expert: Jim Pfister - 10/24/2009

Question
QUESTION: Hi Jim,

You seem to be extremely knowledgeable on the subject, so I thought I would ask you a question I am having great difficulty answering:

I am starting a business that produces ready made soups to sell in stores and I would like to package the soups in milk containers as I need the packaging to be recyclable and able to be heated in the microwave. As my soups are made without any preservatives or additives, the shelf life is very short: 2-4 days even. As you can imagine, a shelf life this short will create huge losses when the product is no longer 'good'. I have read that packaging a product in a certain manner can extend the shelf life, but I'm afraid I have no idea how to do this with the milk carton container. Any suggestions or advice would be greatly appreciated! Thank you so much for taking the time to read this.

Kind regards,
Bonnie

ANSWER: Bonnie,
A couple of points:
1. Is it possible to can your soup? After all, metal is the ultimate recyclable. And what about glass jars?
2. Is it possible to keep the soup refrigerated? Most products in paperboard (milk) cartons are kept this way.
3. You could do aseptic packaging, but there's no way that's feasible on a small scale.
4. Lastly, what is it that makes the shelf life so short? Could you adjust your recipe?

---------- FOLLOW-UP ----------

QUESTION: Wow, thank you for your quick reply!

1. I'm afraid I'm pretty set on the paperboard. It is one of the factors that will set my products apart from the competition: Campbells Soup, etc. I'd prefer not to use glass jars as the soup isn't very aesthetically pleasing, an issue one of my competitors has as they use glass jars.

2. Absolutely, the product would be refrigerated.

3. I'm starting from home, so it's very small scale to start with.

4. Maybe 2 days is a conservative estimate, but I would prefer to err on the side of caution and underestimate at this point. My homemade soup kept in the fridge, is only good for about 4 days. Possibly because all contain milk and or cream?

I have just spoken to my Mum and she has suggested vinegar or lemon juice to increase the shelf life. What do you think?

Thanks again,

Bonnie

ANSWER: Bonnie,
1. If you are stuck on paperboard, then having a foil substrate in the laminate will greatly improve storage.
2. Anything you add to the formula that is acid, and consequently lowers the pH, will also promote longer shelf-life. The downside, though, are the possible negative effects on your flavor and consistency.

---------- FOLLOW-UP ----------

QUESTION: Hi Jim,

Another question I'm afraid. I've received the following email in response to how the soups are produced preservative free, but have such a long shelf life (up to 60 days refrigerated) This is the response:

The way we achieve shelf life stability is due to innovative technology of cooking. Our products are cooked at high temperature and immediately after that are fast chilled. This creates a vacuum like property within the container and protects the product which if properly refrigerated at all times stays shelf stable and delicious. We proudly label our products with Preservative free mark to assure our customers none are used when producing.

Would you by any chance know the name of this chilling process, or which equipment is used to do this? I'd like to find out as much as possible to see if I can replicate the process myself.

Thanks so much in advance, you've been so helpful already!

Answer
Bonnie,
I am not sure. But I can tell you that they are not filling pouches. Must be cans or jars.

Part of the problem with using non-specific terms - like "fast" - is that it tells you nothing. What is fast? 3 minutes? 10 minutes? 1 hour? And what is "high" temperature? They could be doing a normal hot-fill process - which could be described just as they've done!

The problem in both heating and cooling is uniform heat transfer. All of the heat transfer occurs with that small amount of product thats touching the sides of the container. The product must be moved around to make sure new product particles are contacting that surface. Much like the way you stir something in a pot to make sure it cooks uniformly.

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