Handbook of Hygiene Control in the Food Industry

Table 36.4

Selected published surface hygiene swabbing protocols (adapted from

Davidson, 2001)

Sampling variable

Collins

et al.

(1989)

Roberts

et al.

(1995)

Harrigan (1998)

Type of swab

Cotton wool or alginate

Cotton wool

Cotton wool or alginate

Area of surface sampled

5 cm



5 cm

5 cm



5 cm

Not specified

Swabbing protocol

Swab within 25 cm

2

card or

cellophane template area usingone swab

Using aluminium template, swabentire area using two swabs, onemoist and one dry, rotating swabs.Return both swabs to one diluenttube

Swab predetermined area byrubbing firmly over the surface inparallel strokes, with slow rotationof the swab

Type of diluent

Nutrient broth

MRD or ‹ St Ringers

‹ St Ringers

Release method

Soak and squeeze swab

Shake until cotton wool brokendown into fibres

Agitate/shake swab in tube up anddown 10 times

Type of culture media

Not specified

Plate count agar

Nutrient agar or trypticase soyaagar

Cultivation/plating method

Not specified

Spread/pour plates

1 mL pour plates for cotton swabs,0.1 mL and 1 mL plates foralginate swabs

Time and temperature of samplestorage /incubation

Not specified

Not specified

Not specified

Time and temperature ofincubation

Not specified

30 ÎC, 48±72 hours

Not specified

Expression of results

Count/25 cm

2

Count/cm

2

Count/cm

2

Dacron is now the most widely used `bud' material. MRD

= maximum recovery diluent