Testing cultures before use
Testing cultures before use
Is there a definitive test for the viability of the sausage cultures before we use them in a batch of sausage. I have some that have been stored at minus 6° F for more than a year.
Ross- tightwad home cook
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Baconologist
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Ross
I had a batch of culture that was out dated 6 months from the date I purchased it! I made a batch of semi cured pepperoni, not realizing the culture was dated back 7 months from date of purchase, and the pepperoni went south. It was a small batch and I`m sure it was the culture. The pepperoni cured, but just did not look right, it lost its color and again, I believe it was the expired culture. I now date, vacuum seal my culture and freeze it after every use.
Wally
I had a batch of culture that was out dated 6 months from the date I purchased it! I made a batch of semi cured pepperoni, not realizing the culture was dated back 7 months from date of purchase, and the pepperoni went south. It was a small batch and I`m sure it was the culture. The pepperoni cured, but just did not look right, it lost its color and again, I believe it was the expired culture. I now date, vacuum seal my culture and freeze it after every use.
Wally
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Chuckwagon
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Hi Ross, you ol` salty, sailin`, sourdough!
Normally, testing of lactobacillus plantarum, under aerobic or anaerobic conditions, is done using a synthetic lactose medium as a culture. Although the investigation of substrate concentration on cell growth is usually the primary objective, the effects of pH are usually also easily determined using the same test. Optimum pH for cell growth and acid production is between 5 and 6 and it should be noted that anaerobic fermentation produces a higher lactic acid yield of about 2.3 times than for aerobic fermentation. Cell growth rate is about two times higher, but cell yield is only about 80% of that for aerobic fermentation. The high lactic acid yield (0.95∼1.03 (w/w), the complete conversion rate 1.05 (w/w)), tolerance of low pH conditions, and the high cell growth rate, indicate the use of lactobacillus plantarum in lactic acid fermentations for our purposes as well as in those in many huge industrial applications, is ideal. The optimum temperature for the growth of lactobacillus plantarum is 86°F. with a salt limit of 13%. Fermentation studies in batches with no pH control indicate that lactose slightly inhibits cell growth in the exponential growth phase but there are no effects in the stationary and death phases. If you would like to see how commercial producers test pH, click on this link: http://www.eutechinst.com/products/portables/ph56.htm
However, for our purposes, it is more economical to simply use litmus paper. Although we`d be looking for "any" increase in acidity, it may not be the best result for which we are looking. A simple litmus test is surprisingly accurate and would let us know if there is reasonable strength remaining. Be sure to measure the acidity of the medium before you add the lactobacillus, then again after it has been added and had time to develop.
U.S. Government FSIS meat inspectors and professional commercial sausage makers use battery powered devices for measuring the acidity (pH) in meat as well as Water Activity (Aw). The PawKit (for testing Aw) is a quality-made product by Decagon Devices Incorporated in Pullman, Washington. (www.decagon.com). It weighs only 4 ounces and is incredibly accurate. However, the last time I checked the price of a PawKit water activity meter, it was over three hundred dollars! To test pH in meat, a Hanna pH test meter is available from Hanna Instruments in Woonsocket, Rhode Island. (www.hannainst.com/usa).
Home hobbyists, needing a convenient and inexpensive method of testing pH acidity have found a product called "pHydrion Microfine Testing Strips". The product is available from any pet store that sells fish or most sausage equipment suppliers for about $12.99 for a dispenser of 15 feet of litmus paper testing paper strips. The product is available in two ranges, first for testing acidity from 3.9 to 5.7 pH, and second, for testing acidity from 4.9 to 6.9 pH. Testing is done by color comparison and although the results may be less accurate than an electronic PawKit can provide, test strips are a bargain at about 6 cents per test!
To test, tear off an inch of testing paper, dip it into the 86°F. prime test medium, match it to the color chart on the side of the dispenser, and then record the data. Next, add the suspected morbid lactobacilli and stir it slightly. Allow a couple of hours for any indication of growth before testing again. Record and compare. No technical training required, although you should take one more thing into consideration.
Compare a fully-effective Bactoferm culture with a brand-new flashlight battery. As your flashlight lies in a drawer unused, the battery`s power diminishes with time. After several month`s time, the bulb becomes only barely lit by the nearly-dead battery. Live lactobacillus plantarum cannot be expected to remain at its full strength over time, nor will it perform with any satisfactory degree of expectation when the living organism has nearly expired. My advice is to follow the six-month shelf life expectancy closely, and then as Uwanna suggests... vac-sealing and sub-zero freezing any remainder. If you haven`t used the remainder within half a year, toss it.
Best Wishes,
Chuckwagon
Normally, testing of lactobacillus plantarum, under aerobic or anaerobic conditions, is done using a synthetic lactose medium as a culture. Although the investigation of substrate concentration on cell growth is usually the primary objective, the effects of pH are usually also easily determined using the same test. Optimum pH for cell growth and acid production is between 5 and 6 and it should be noted that anaerobic fermentation produces a higher lactic acid yield of about 2.3 times than for aerobic fermentation. Cell growth rate is about two times higher, but cell yield is only about 80% of that for aerobic fermentation. The high lactic acid yield (0.95∼1.03 (w/w), the complete conversion rate 1.05 (w/w)), tolerance of low pH conditions, and the high cell growth rate, indicate the use of lactobacillus plantarum in lactic acid fermentations for our purposes as well as in those in many huge industrial applications, is ideal. The optimum temperature for the growth of lactobacillus plantarum is 86°F. with a salt limit of 13%. Fermentation studies in batches with no pH control indicate that lactose slightly inhibits cell growth in the exponential growth phase but there are no effects in the stationary and death phases. If you would like to see how commercial producers test pH, click on this link: http://www.eutechinst.com/products/portables/ph56.htm
However, for our purposes, it is more economical to simply use litmus paper. Although we`d be looking for "any" increase in acidity, it may not be the best result for which we are looking. A simple litmus test is surprisingly accurate and would let us know if there is reasonable strength remaining. Be sure to measure the acidity of the medium before you add the lactobacillus, then again after it has been added and had time to develop.
U.S. Government FSIS meat inspectors and professional commercial sausage makers use battery powered devices for measuring the acidity (pH) in meat as well as Water Activity (Aw). The PawKit (for testing Aw) is a quality-made product by Decagon Devices Incorporated in Pullman, Washington. (www.decagon.com). It weighs only 4 ounces and is incredibly accurate. However, the last time I checked the price of a PawKit water activity meter, it was over three hundred dollars! To test pH in meat, a Hanna pH test meter is available from Hanna Instruments in Woonsocket, Rhode Island. (www.hannainst.com/usa).
Home hobbyists, needing a convenient and inexpensive method of testing pH acidity have found a product called "pHydrion Microfine Testing Strips". The product is available from any pet store that sells fish or most sausage equipment suppliers for about $12.99 for a dispenser of 15 feet of litmus paper testing paper strips. The product is available in two ranges, first for testing acidity from 3.9 to 5.7 pH, and second, for testing acidity from 4.9 to 6.9 pH. Testing is done by color comparison and although the results may be less accurate than an electronic PawKit can provide, test strips are a bargain at about 6 cents per test!
To test, tear off an inch of testing paper, dip it into the 86°F. prime test medium, match it to the color chart on the side of the dispenser, and then record the data. Next, add the suspected morbid lactobacilli and stir it slightly. Allow a couple of hours for any indication of growth before testing again. Record and compare. No technical training required, although you should take one more thing into consideration.
Compare a fully-effective Bactoferm culture with a brand-new flashlight battery. As your flashlight lies in a drawer unused, the battery`s power diminishes with time. After several month`s time, the bulb becomes only barely lit by the nearly-dead battery. Live lactobacillus plantarum cannot be expected to remain at its full strength over time, nor will it perform with any satisfactory degree of expectation when the living organism has nearly expired. My advice is to follow the six-month shelf life expectancy closely, and then as Uwanna suggests... vac-sealing and sub-zero freezing any remainder. If you haven`t used the remainder within half a year, toss it.
Best Wishes,
Chuckwagon
If it looks like a duck, walks like a duck, and quacks like a duck, it probably needs more time on the grill! 
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Chuckwagon
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Ross, let us know how the testing goes. I have a bunch of various cultures that are way past their expiration dates, but they are in a -6° F freezer. In the past, I did test some that were past their prime by stirring some into distilled water that had some dextrose added. After incubating for 48 hours at 90° F I tested the pH using a digital meter and found it was around pH 5, so I was able to use it, but I added a lot more dry culture than usual. Spending $15 or more for a packet of culture (plus shipping) adds up quickly so using what you have left makes sense.
Rudy
