Sop for microbial Air Sampler

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This Document describes (Standard Operating procedure) Sop for Operation and Maintenance of microbial air Sampler.

Sop for Operation and Maintenance of microbial air Sampler.

I. Purpose & Scope:

  • The purpose of this SOP is to lay down the procedure for Operation and Maintenance of microbial air Sampler
  • This Standard operating procedure shall be applicable for Operation and Maintenance of microbial air Sampler in the Microbiology section of Quality Control Department

II. Responsibilities:

  • All Quality Control and Quality Assurance personnel shall be responsible to follow and implement this SOP.

III : Introduction and Procedural Part:

Principle of Microbial Air Sampler :

Air is aspirated through a perforated lid, and impacted onto the surface of growth media in a standard 90 mm petri dish. Microorganisms impact the culture media and the colonies can be counted after incubation period. The system measures the inflow of air, regulates the aspirated volume to a constant value of 100 lit/min.

Operating Procedure of Microbial Air sampler :

Switch ON/OFF :

      • For switching ‘ON’, Press and hold the ON/OFF Key for about one second.
      • For switching ‘OFF’, Press and hold the ON/OFF Key for at least one second, or press the ‘stop’ key on the remote control.
      • Starting a sampling program :

To start a sampling cycle, proceed as follow,

SAMPL’AIR  <    SAMPLE  > → press enter  →  SAMPLE <       1000L      > → Press enter → 1000 L start →  PROGRAM IS STARTED

  • Select the ‘Sample’ menu, and then press ‘Enter’.
  • Select the program to be started using directional arrow. The chosen program is displayed on the lower line, press ‘Enter’. (Possibility of creating or deleting a program as well).
  • The Start screen is displayed to begin the sampling, press ‘Enter’ or the ‘Start’ key from the remote control.
  • The other Sampling programs may be deleted or replaced by programs created by the operator (up to 10 sampling programs).
  • To select the sampling program you wanted to start, use the directional arrow and confirm your choice by pressing ‘Enter’.

Positioning the Petri dish and starting the sampling :

  • Choose the program to be started (1000Lit Volume or 10 min Sampling time)
  • Place the sampling head vertically. Pull up the stainless steel grid to remove it from the unit; place the grid on a clean surface.
  • Fit the Petri dish on the clips and make sure that dish is placed horizontally.
  • The clips help with adjusting the petri dishes in the center above the turbine. Make sure that the dish is properly inserted.
  • Remove the Petri dish lid and put it on a clean surface. Place the Sample air lite grid back. The Sampler is ‘ready’ to start a cycle.
  • At the end of the sampling, a signal tone sounds and the message “End of sampling” is displayed. Press Enter to stop the signal and go back to the SAMPLE menu for next sampling.
  • Remove the impaction grid and close the Petri dish. Place the Petri dish into an incubator for further incubation. Report the details of usage, in Instrument usage record , refer Annexure- I.
  • In case of problems occurs during the cycle, the error codes are successively displayed at the end of the cycle. Press ENTER to acknowledge each error message. Some errors may stop.

Counting and Calculation :

  • After incubation, count the number “n” of CFU which have grown.
  • In order to take into account the probability of having impaction of 2 or more microorganism, an algorithm is applied according to Peto and Powel work.

En = {   }

T = Number of holes in the sampling grid (258 holes)

n = Number of numerated colonies

En is the estimated number of viable micro-organisms giving n positive     impacts, when using a grid whose number of holes = T.

This formula suggests that the micro-organisms flow stops when a micro- organism reaches the hole ‘n’.

This flow being irregular, the estimated number of particles, when n impacts are observed, has to be equal or superior to En, but inferior to E (n+1).

The adjusted number N is obtained using:

N =  {E n + (E n +1 –1)}

  • Consult the Table- I for Finding Probable No. of Colonies. Table-I indicates the ‘n’ value (No. of colonies actually numerated) corresponding to ‘N’ (Probable No. of viable impacted microorganisms – either estimated or adjusted).

Table-I

n N n N n N n N n N n N
1 1 31 33 61 70 91 112 121 163 151 227
2 2 32 34 62 71 92 114 122 165 152 229
3 3 33 35 63 72 93 115 123 167 153 232
4 4 34 36 64 74 94 117 124 169 154 234
5 5 35 38 65 75 95 118 125 171 155 237
6 6 36 39 66 76 96 120 126 173 156 239
7 7 37 40 67 78 97 122 127 175 157 242
8 8 38 41 68 79 98 123 128 177 158 245
9 9 39 42 69 80 99 125 129 179 159 247
10 10 40 43 70 82 100 127 130 181 160 250
11 11 41 45 71 83 101 128 131 183 161 252
12 12 42 46 72 84 102 130 132 185 162 255
13 13 43 47 73 86 103 131 133 187 163 258
14 14 44 48 74 87 104 133 134 189 164 260
15 15 45 49 75 89 105 135 135 191 165 263
16 17 46 51 76 90 106 137 136 193 166 266
17 18 47 52 77 91 107 138 137 195 167 269
18 19 48 53 78 93 108 140 138 197 168 272
19 20 49 54 79 94 109 142 139 200 169 275
20 21 50 56 80 96 110 143 140 202 170 278
21 22 51 57 81 97 111 145 141 204 171 280
22 23 52 58 82 99 112 147 142 206 172 283
23 24 53 59 83 100 113 149 143 208 173 286
24 25 54 61 84 102 114 150 144 211 174 290
25 26 55 62 85 103 115 152 145 213 175 293
n N n N n N n N n N n N
26 27 56 63 86 105 116 154 146 215 176 296
27 29 57 64 87 106 117 156 147 218 177 299
28 30 58 66 88 108 118 158 148 220 178 302
29 31 59 67 89 109 119 160 149 222 179 305
30 32 60 68 90 111 120 161 150 225 180 309

Precautions during operation of microbial air sampler:

  • To prevent fire or shock hazard, do not expose this device to rain.
  • Do not try to charge a fully charged battery; this may reduce its performance.
  • The battery becomes preferment more quickly if you charge it at room temperature, and when the low battery warning occurs.
  • The depth of the agar in the Petri dish should be reproducible; agar surface should be flat and leveled and no present any dryness.
  • The total charging time depends on the energy level of the battery. It is recommended to let the Sample air lite loading at least 5 hours after a sampling campaign.

Cleaning and Maintenance of microbial air sampler :

  • Air Sampler shall be cleaned after each sampling campaign.
  • External surfaces and sampling grid shall be cleaned with 70% IPA in between each sampling.
  • The stainless steel impaction grid shall be autoclaved (in Accessories Sterilization Load) between each sampling campaign.
  • Do not use oxidizing agent such as hydrogen peroxide when cleaning the unit.
  • Do not use bleach on the micro perforated sieves.

Calibration:

  • Calibration of the microbial Air Sampler shall be done by external agency, once in a year or after any major maintenance.

 

Instrument usage Record of microbial Air Sampler

Instrument I.D. : ____________

Date of Usage Used for

Usage time

 Cleaning Status Done By Checked By
From To

 

 

Reviewed By :—————————                                           Verified By :——————-

(Department Head)                                                                            (QA)

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