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Appendix F Bacteriological Study of Beef Carcasses in Quebec This study is described here as an example of how to collect and analyze data for microbiological determination on beef carcasses. Purpose of the Study To make bacterial counts on some beef carcasses, from the dressing stage up to boning, in three registered Quebec plants and to assess whether a specific stage of processing can be identified with regard to its contribution to the total bacterial count. Materials and Methods 3 abattoirs IS carcasses/plant ~ stamp (see annex 2) and an inker 2 pincers, 2 scalpel handles, disposable blades 2 bottles of alcohol 2,000 Wiripack bags (54 carcasses x 7 sites x 6 work areas) 54 Ice paks (3 plants x 3 days x 6 paks) 4 insulated foam boxes for samples 2 calibrated thermometer-hygrometers 2 calibrated meat thermometers 60 data collection sheets 1,620 samples (laboratory costs) For reasons of confidentiality, the establishments concerned wait be called A, B. and C. At each one, 18 beef carcasses (cows) will be marked at the dressing stage. A half-day pilot project will be conducted at least 3 weeks before the project starts to validate procedures. This pilot project will consist of taking samples from three carcasses selected at random during the morning at one establishment only. This will also allow the three Veterinarians in Charge, who will be responsible for collecting samples in their respective plants, to become familiar with all aspects of the experimental procedure. This exercise will also verify whether there are variations in bacteria count (total count) on the surfaces of the carcasses between a carcass put to one side in relation to another in the center of the cooler. The rate of flow (volume/mL~ture) and pressure of the water used as well as the average time spent on washing a half carcass (average washing time for 10 half- carcasses) will be recorded. 90
Collection of data specific to each establishment will be done before the study begins. At that time, the procedure will be explained to the plants' management. The carcasses will be selected at random during the day and must be handled as usual, that is, with no extra sanitation measures taken. They will be set aside when put into the cooler. At each plant, samples from three carcasses will be taken each Tuesday, Wednesday, and Thursday for 2 weeks. The first week, the three carcasses will be selected in the morning; the second week, in the afternoon. The carcasses will be selected at random at fixed times: 9:00, 10:00, and 11:00 a.m., and 1:45, 2:15, and 3:15 p.m. To achieve uniformity of sampling techniques, the following procedure must be followed. After skinning, the selected carcass will be identified with a label containing a reference number. This number will be written on a data sheet (see Annex 1) to be used for this carcass. Samples from the carcasses must be taken with sterile instruments (flame-sterilized scalpels, pincers, and stamps). The selected carcass will be marked with the stamp (see Annex 2) in the areas listed below (see Annex 3): 1. Brisket 2. Hind hock--cranial surface 3. Flank 4. Front shank--caudal surface 5. Neck--lateral surface at about 10 cm from the end 6. Rump--at about 5 cm from the pelvic cavity 7. Leg--in the middle at the semitendinous/semimembranous area The needles of the stamp will delineate three 2 cm by 3 cm areas. The areas should be considered as being numbered as shown in Annex 3, and samples should be taken in that order. Thus, at the abattoir, all the No. 1 samples will be taken with a sterile scalpel and pincers before trimming from the seven areas mentioned above. After washing, when the carcass goes into the cooler, the No. 2 samples will be taken and so on. In the cutting room, the No. 3 samples will be taken from the seven areas before boning. The samples should be cut 0.5 cm thick and follow the pattern marked by the stamp. They should never be touched with hands. They will then be placed in sterile bags (Wirlpack) and refrigerated at 2°C until analyzed. The samples must be refrigerated and sent to the laboratory by courier as soon as possible after slaughter-- the same day, if possible, or the next day at the latest. CAUTION! You must be sure to identify each sample clearly by writing on the plastic bag the carcass reference number, the sample area, and sequence (example: C03-1-A). The same number will be marked on the carcass with indelible pencil to avoid loss of data. In the cutting room, in addition to sampling the carcasses identified in the 91
slaughter room, IS other carcasses in each cutting establishment will be selected at random one Monday from among those that have been in the cooler over the preceding weekend. This sampling wall verify whether this waiting period can lead to higher counts. At the laboratory, the samples will be handled as follows: they will be homogenized and cultured in the usual way for doing total bacterial count. Total bacteria count at 37°C wild then be taken. Relative humidity and temperature readings will be taken as follows: 1. In the evisceration area, read and note the temperature and relative humidity at about 30 cm (! foot) from the carcass at the height of the patella and the brisket. 3. When the carcasses are put into the cooler, take the same readings. Before the quarters are boned, take the internal temperature of the quarters 0.5 cm below the surface. 4. In the cutting room, record the temperature and humidity of the room at about 30 cm (I foot) from the surface of the boning table as the quarters of the carcasses being sampled are boned. After boning, and after the samples have been taken, take a temperature reading at the neck and the rump at 0.5 cm below the surface, near the sample area. Results The results obtained can be expressed with tables of the following types: 1. Bacterial counts at different work areas at each of the three abattoirs. 2. Bacterial counts at the different sample sites at each of the three abattoirs. 3. Other data collected (e.g., temperatures, relative humidity) at the three establishments. 4. Three-dimensional graphic: sampling site compared to bacteria count and sampling day. Bacterial count and relative humidity. 92
6 8. 9. Bacterial count and temperature of slaughter floor. Bacterial count after evisceration compared to transit time on the slaughter floor. Bacterial count before cutting and total storage time. Bacterial count and type of washing. 10. Average reduction of count and type of washing. At. Bacterial count after cutting and temperature after transport or after cutting. 12. Bacterial counts in the morning and in the afternoon. 93
Annex ~ Data Sheet for Establishment Establishment Type of skinning machine: upward downward roll-off Spray chilling system yesno Attach details of use Types of carcass washing: manual 4. Approximate flow rate (vol/min) 5. Pressure of water used: mechanical liters/minute 6. Average washing time (half carcass): seconds 7. Are carcasses transported by truck to the boning room? Carcass Reference no.: C- DATE: / / Carcass of dairy_beef cow Carcass weight before chilling: _kg yes no i Skinning Date: / /: Time:_: put reference number on carcass, label, and form 94
Evisceration Temperature + relative humidity of carcass (front quarter) °C % Temperature + relative humidity of carcass (hind quarter) °C % Note time Before Trimming Mark carcasses with stamp Holding Rail Sterilize instruments in flame and take No. ~ samples Weighing Note warm weight of carcass Placed In Cooler Note time Temperature + relative humidity of carcass (front quarter) °C % Temperature + relative humidity of carcass (hind quarter) °C % Sterilize instruments in flame and take No. 2 samples Transport (Optional) Before Cutting Note date:_ / /: Time: : Temp. of quarters-- front _ °C -- hind °C Sterilize instruments in flame and take No. 3 samples During Cutting Temperature + relative humidity of piece during boning of front quarter °C % After Cutting Sterilize instruments in flame and take No. 4 samples. Temperature of neck 0.5 cm below surface °C Temperature of rump 0.5 cm below surface °C 95
Number of Samples Taken per Week Per Establishment Abattoir Cutting Cutting Cutting Total (carcass) (piece) (suppl. care.) Monday -- -- -- 63 63 Tuesday 42 -- -- -- 42 Wednesday 42 21 6 -- 69 Thursday 42 21 6 -- 69 Friday -- 21 6 -- 27 Total 126 63 18 63 270 Total number of samples taken: 2 weeks per establishment = 2 X 270 = 540 For the three abattoirs: 3 x 540 = 1,620 samples 96
Annex 2 Needle Point Stamp for Marking Samples to be Taken 1~ // 1 // /11 111. 111 // /~ Stamp ~ ~1~ 1111111111111 _ ~ Imprint 2 cm ................ · - .~e-e.~.-- eee. · · · · · · · · · · · ~.e--e.-..~e.~e · · · · · · · .- · · · ~ ~ ~ · ~ ~ ~ ~ ~ ~ ~ · ~ ~ ~ 3 cm ~ 97
Annex 3 Areas from Which Samples are to be Taken and Location of Points at which to {eke Temperature and Relative Humidity Readings Stamp Fit-' _ / ~ ~,4_ / 4 ~0 / 3 Thermometer / ~ ~< hygrometer ~\ 5 \ 98 30 cm 30 cm :~~ ,/7 1 2, · · ·e *e ~e ;~5 Thermometer hygrometer \ / /'I 1
