The tables of data from the gassy cheese article.Table 1. Major microbial groups that can produce gas in cheese |
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Microbial group |
Substrate |
Gaseous products |
Clostridia |
Lactate |
CO2, H2 |
Lactobacilli |
Lactose Citrate |
CO2 |
Streptococci |
Urea |
CO2 |
Coliforms |
Lactose |
CO2, H2 |
Yeasts |
Lactose |
CO2 |
Lactococci |
Citrate |
CO2 |
Bacillus species |
Lactose |
CO2, H2 |
Leuconostocs |
Lactose/citrate |
CO2 |
Propionibacteria |
Lactate |
CO2 |
Notes:1 Streptococcus thermophilus can also produce gas from other substrates.
Table 2. Microbiological analysis of blown and normal cheese from factory X |
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CFU/g |
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Blown cheese-A |
Blown cheese-B |
Normal cheese |
|
'Total count' on milk agar |
1.3 x 10 8 |
6 x 107 |
2 x 107 |
Yeasts and moulds |
<10 |
<10 |
<10 |
Coliforms |
<10 |
<10 |
<10 |
Catalase-negative citrate utilisers(1) |
8 x 107 |
4 x 107 |
<1 x 106 |
Clostridia |
<1 x 10 2 |
<1 x 102 |
<1 x 102 |
Group D streptococci |
<1 x 102 |
1.3 x 103 |
2 x 102 |
Lactobacilli(2) |
4.1 x 104 |
4.1 x 105 |
1 x 103 |
Aerobic sporeformers |
1 x 102 |
1 x 102 |
1 x 102 |
TABLE 3. Relationship between citrate level in cheese, ex-press, and gas production in Cheddar cheese |
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Days after manufacture |
Starter code |
Milk citrate level (% w/w) |
Cheese citrate level(2) (% w/w) |
Condition of barrier bag(3) |
1 |
1607 |
ND |
0.05 |
Blown |
3 |
1607 |
ND |
< 0.001 |
Slack |
15 |
1607 |
0.17 |
0.09 |
Blown |
29 (vat 1) |
1607 |
0.17 |
0.01 |
Blown |
29 (vat 3) |
SLA(1) |
0.17 |
0.21 |
Blown |
53 |
MS(1) |
0.17 |
0.19 |
Tight, no gas |
60 |
1607 |
0.18 |
0.14 |
Blown |
TABLE 4. Characteristics of Rogosa-agar isolates from a commercial mixed-strain culture |
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Isolate |
HM8/4 |
HM8/11 |
HM8/10 |
HM8/14 |
Morphology |
Cocco/ bacillus |
Cocco/ bacillus |
Cocco/ bacillus |
Cocco/ bacillus |
Gram reaction |
+ |
+ |
+ |
+ |
Catalase |
- |
- |
- |
- |
NH3 from arginine |
- |
- |
- |
- |
Nitrate reduction |
- |
- |
- |
- |
Lactic acid (isomer present) |
(D) |
(D) |
(D) |
(D) |
Acid produced in RSM(1) |
0.25% |
0.20% |
0.48% |
0.39% |
Gas from glucose |
+ |
+ |
+ |
+ |
Gas from gluconate |
+ |
+ |
+ |
+ |
Acid from arabinose |
- |
- |
- |
- |
Acid from xylose |
(+) |
- |
(-) |
+ |
Acid from maltose |
+ |
+ |
+ |
+ |
Growth at 40ºC |
- |
- |
- |
- |
Growth at 10ºC |
+ |
+ |
+ |
+ |
Growth at 6ºC |
- |
+ |
+ |
- |
Growth in 6% NaCl |
+ |
+ |
+ |
+ |
Growth in 6.5% NaCl |
- |
- |
- |
- |
Citrate utilisation |
+ |
+ |
+ |
+ |
TABLE 5. Maximum volumes 1,2 (L) of carbon dioxide available from citrate and lactose in cheese (3) |
% substrate (w/w) |
Volume of CO2(1) |
|
Citrate(4) |
Lactose(5) |
|
0.8 |
NC |
18.8 |
0.5 |
NC |
11.8 |
0.2 |
12.6 |
4.7 |
0.1 |
6.3 |
2.4 |
0.02 |
1.3 |
0.48 |
Notes: |