Microbes are everywhere, all the time. Your body contains around 30 trillion human cells, and even more microbial cells. The breath you just took probably inhaled a few microbes—more than a few if you’re around other people, pets or livestock. That means microbes are circulating in packing plants, too. Most microbes are harmless, but some can shorten the shelf-life of beef, and a few (like Shiga-toxin producing E. coli or STEC) can cause food poisoning.
Beef is an excellent nutrient source for people. It’s also an excellent nutrient source for microbes. If microbes establish themselves on conveyor belts and other processing equipment, they have a ready food source to support their growth. As a result, Canadian packing plants work very, very hard to keep their facilities clean and their beef products safe. Facilities are cleaned after each shift. They start by scraping away visible contamination, then pressure washing the conveyor belts, equipment and floors (Step 1). In Step 2, a detergent is applied to break down fat residues, then rinsed off. Finally, a sanitizer is applied to kill microbes that may not have been washed off (Step 3).
Dr. Xianqin Yang of Agriculture and Agri-Food Canada’s (AAFC) Lacombe research station and co-workers studied how microbial numbers change through the three-step cleaning process (Effects of Sanitation Practices on Microbial Dynamics in Meat Processing Environment).
What They Did
In collaboration with a major beef packing plant, the team collected samples from conveyor belts, floor drains and air before cleaning started, after Step 1 (pressure washing), after Step 2 (detergent) and after Step 3 (sanitizing). Bacteria were counted and identified in each sample.
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