The tables of data from the gassy cheese article.

Table 1. Major microbial groups that can produce gas in cheese

Microbial group

Substrate

Gaseous products

Clostridia
  Clostridium tyrobutyricum

Lactate

CO₂, H₂

Lactobacilli
  E.g. Lactobacillus brevis
  E.g. Lactobacillus casei

Lactose

Citrate

CO₂

Streptococci
  Streptococcus thermophilus¹

Urea

CO₂

Coliforms

Lactose

CO₂, H₂

Yeasts

Lactose

CO₂

Lactococci
 Lactococcus lactis ssp. lactis biovar. diacetylactis

Citrate

CO₂

Bacillus species
  Bacillus subtilis

Lactose

CO₂, H₂

Leuconostocs
  E.g. Leuconostoc mesenteroides
  E.g. Leuconostoc dextranicum

Lactose/citrate

CO₂

Propionibacteria
  Propionibacterium shermani

Lactate

CO₂

Table   2. Microbiological analysis of blown and normal cheese from factory X

CFU/g

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

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

Notes:

(1) Defined multi-strain cultures that did not contain citrate utilising strains.
(2) Cheese analysed immediately after pressing for citrate (12 hours).
(3) Cheese was stored at 7C for 6 weeks before examination.
ND - not determined

TABLE 4.   Characteristics of Rogosa-agar isolates from a commercial mixed-strain   culture

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:

(1) Volumes at standard temperature and pressure (STP)
(2) No allowance made for adsorption/solution. Values are rounded
(3) Cheese mass 18 kg
(4) Assuming 3 moles of CO2 produced from 1 mole citrate
(5) Assuming 2 moles of CO2 produced from 1 mole lactose
NC. Not calculated. Citrate levels of >0.2% w/w are not normally found in Cheddar cheese.

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