I'm sure we can help here.
Usually key items in yogurt manufacture are:
pasteurization to kill pathogens
filtration to remove foreign bodies
achieving a low pH (high acidity) within a certain timescale to prevent the growth of pathogens
hygiene of personnel/equipment to prevent contamination of the product
Please provide a 'process flow' - the steps to making the yogurt. Also a list of ingredients and the stages they are added and confirm the packaging or what you are filling the finished yogurt into.
Thanks for your response. Here's our process:
1. Receive 40-120 gallons milk 1x per week from distributor (depending on season – summer is very busy and winter is very slow for us)
2. Check milk temp to make sure its below 41 degrees F
3. Transfer milk to walk-in cooler
To make yogurt:
4. Calibrate thermometer in ice/water slush
5. Pour 40 gallons whole milk in yogurt kettle (our milk is already homogenized and pasteurized)
6. Stir milk every few minutes until it reaches 190 degrees F
7. Cool to 115 degrees F (our kettle uses cold water to cool the milk. This step usually takes about 1 hour)
8. When at 115 degrees F, turn off cold water
9. Pour 2.5 gallons milk into a 5 gallon bucket
10. Slowly temper 2 quarts yogurt into 2.5 gallons of milk using stainless steel whisk (we use yogurt from the last batch, or store-bought yogurt as our “culture” for the new batch – if this won’t be approved or if there’s a better Greek yogurt culture, we can get a dry culture, etc.)
11. Slowly pour 2.5 gallons of milk/culture mix back into yogurt kettle and stir well with drill (we use a drill with mixing rod attached to it)
12. Place a spacer bucket in the kettle and close/lock kettle lid (we had a spacer bucket designed to sit in the kettle so after the yogurt ferments we can put ice in the spacer bucket in the middle of the yogurt to help it cool quicker)
13. Let yogurt ferment in locked kettle undisturbed for 12-18 hours until yogurt forms (we need help with this step since we base the finished product on taste and texture rather than exact time, like it should be done – see notes below)
14. Wash whisk, drill mixing rod, thermometer and 5 gallon bucket
15. Once yogurt has formed, add ice to spacer bucket and turn on cold water
16. Let yogurt cool in kettle for 2 hours
17. Once cooled, pour yogurt into 4 five-gallon cotton bags
18. Hook yogurt bags onto sides of large push cart container
19. Put push cart container in walk-in cooler and let yogurt bags strain in cooler
20. Wash yogurt kettle and spacer bucket, dry both, store spacer bucket in kettle and close/lock lid
21. Pour strained yogurt into 1 large bin and squeeze excess yogurt out of bags
22. Place bin in walk-in cooler
23. Wash yogurt bags and hang to dry
24. Empty excess whey from push cart container and wash
We were asked to develop a HACCP plan just for our Greek yogurt process, which involves the above steps.
Though we weren’t asked to develop a plan for the next step, from there we make tzatziki by adding cucumbers, oil, vinegar, lemon juice, salt and garlic to the yogurt. We put the sauce into 1/3 size 6.5 quart stainless steel pans, cover the pans with plastic wrap and write the date the sauce was made on the plastic wrap. Then the 1/3 size pans go back into the walk-in cooler (FIFO style) until we’re ready to use the product. We also portion a very small amount of Greek yogurt (before the sauce is made) into 16 ounce plastic containers with lids, which we sell very few of at the restaurant.
This is the process my parents brought from Greece when they immigrated and the process we’ve used for the past 40+ years in our restaurant. We’ve never had a health issue with it, but I don’t know that the health department will approve our process since the yogurt ferments for so long. Since I’m taking over the restaurant, I want to do things right. We’re more than willing to change our process so long as we can use the same equipment and we can still make a great product that tastes the same. For example, if someone knows the exact minimum amount of time it takes Greek yogurt to form and have the same semi-sour Greek yogurt flavor, I’d like to know so we can be more consistent, rather than waiting 12-18 hours and relying on an individual to determine whether or not it is finished based on taste and texture. Or if using a different culture or process will cause it to ferment quicker, we’ll go for it.
Please let me know your thoughts, and thank you so much for your help.