Friday, June 27, 2014

Managing Risk in Stored Colostrum

On June 23rd I was watching a calf care person get ready to put colostrum into a freezer. She put one self-locking one-gallon freezer back inside another. She poured two quarts of colostrum that had been collected about 20 minutes ago into the bags. The bag went into the freezer - she laid it flat.

What are the risks of bacterial contamination of this stored colostrum when it is thawed and warmed to feed a calf?

  • inoculation with environmental bacteria a the time of collection from the cow - I did not watch her collect the colostrum. However, in this case the dam was milked as soon as she was up after calving and steady on her feet - they have a stall in the calving area to restrain fresh cows for milking. I saw a teat dip container and several soiled disposable towels - so let's assume she did a good job of cleaning up teats before milking.
  • inoculation with environmental bacteria at time of collection from equipment - all the stainless steel equipment, even though soiled with just-collected colostrum, appeared to be well maintained. She poured colostrum from the milker can into a gallon-size plastic pitcher in order to transfer it into the plastic freezer bags - it looked clean but it was a potential source of environmental bacteria.
  • placing the colostrum into the freezer at 90-plus degrees - work that I did several years ago on chilling rates showed that in a household refrigerator a two-quart container of 90F colostrum took 10.5 hours to chill to 40F. I would have preferred that she chilled the colostrum in an ice water bath for 30 minutes to take it down to 60F before it went into the freezer. Chilling time to 40F when the colostrum starts at 60F is only 5.5 hours compared to the 10.5 hours when the colostrum is 90F.
What recommendations would I have for this dairy?

1. Once in a while check teat end preparation with an alcohol pad - it should not come away with manure particles.

2. This farm size predicts one to two calvings a day. That means the dedicated milker unit used at the calving pen sits idle most of the time. I would prefer a quick "pre-use" sanitizing rinse with hot water and household bleach just before milking each fresh cow. 

3. Use a similar "pre-use" sanitizing rinse on the tube feeder used to administer the colostrum and on any other equipment involved in colostrum handling and storage.

4. Chill any colostrum that is to be refrigerated or frozen to 60F before placing it into the cooling unit. 

5. Consider using a 50% liquid potassium sorbate food preservative in colostrum that is to be stored for future use. Click HERE to a protocol for using potassium sorbate.

6. Regularly (once a month, once a quarter) collect 5 or more "as-fed" colostrum samples and have them cultured for bacteria. If nothing grows, great! If many, many bacteria grow fix something.

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