After over a year of cheesemaking, we were getting tired of seeing many of our brined cheeses suffer late blowing, between 1-3 months after making.... They often swelled up, cracked, split the wax, and sometimes ended up looking like a "Swiss" when they had no reason to.... Reading about late blowing here on the CheeseForum (and other places) led me to conclude that the culprit was likely
Clostridium tyrobutyricum spores that survived the pasteurization process in our store-bought milk.... Large-scale P/H milk, which is sourced from multiple dairies, is unlikely to avoid silage in the feed of at least some of the cows, which is where the Clostridium flourishes.... We were convinced that our hygiene was not to blame (my wife was a Dental Assistant, and knows all about sterilizing).... Our cheeses were all edible, never had an off smell or taste (that we noticed), but seeing them swell and split was very frustrating.... It didn't seem to be an issue when the curds were salted directly (eg. a Cheddar), and I found out why from the summary of a scientific report....
This study evaluated the effects of NaCl and ripening time on spore germination of Clostridium tyrobutyricum by analysing the related production of hydrogen in a cheese model. The new approach of this work was to develop a hard cheese model Grana Padano and Parmigiano Reggiano, without the brining stage, that was then cut and ripened at three different times (3, 6, 9 months), freeze-dried and reconstituted with the addition of C. tyrobutyricum spores and different salt concentrations, while maintaining for all cheese models a fixed moisture of 36% ± 1%. Interestingly, a concentration of NaCl near to 0.3% reduced hydrogen production, and therefore germination, at 3 months and completely inhibited it at 6 and 9 months. A 0.5% salt concentration no hydrogen production was observed at all ripening times. In contrast at 9 months of maturation no hydrogen production was observed without any effect due to the salt concentration.
In a brined cheese, the salt content is lower in the center, which is where the germination of the spores starts.... One of the recommended solutions on this forum to late-blowing was to use a culture called "Holdbac", which produces an anti-bacterial agent that prevents the growth of Gram-positive bacteria like Clostridium.... It turns out there are several varieties, and that Holdbac LC was the one I wanted.... Here is the description....
Holdbac LC: For semi-hard and emmental style cheeses. Protects against: Clostridium, Microorganisms, yeasts, moulds and heterofermentative lactobacilli.
Extends shelf life of product. Composition: Lactobacillus rhamnosus.
It isn't cheap, but you don't use much.... The first package I bought was 50 DCU and weighed 8 grams.... The dosage is 5-20 DCU per 100 litres of milk, and I use 1/8 tsp. in our 9 litre makes, but half that much is probably enough.... The second 50 DCU package I bought weighed 30 grams, so more (by volume) would be needed.... One word of caution.... The product is "pelletized", so before you open the foil pouch, run a rolling pin over it to break the pellets down into a fine powder, making it easier to measure small amounts....
Using Holdbac LC was the cure to our late blowing of our brined cheeses.... We haven't had it happen to a single cheese since we started using it.... As an example, our first two Asiagos split, the last one, using Holdbac LC did not.... The same goes for our Edams and Goudas....
Bob
