Food Safety is a Serious Matter

The potential for pathogenic microorganisms exists in virtually all food products. These microbes are capable of causing disease or illness and must be carefully controlled and monitored throughout the food manufacturing process. Recent outbreaks caused by E. coli, salmonella, and listeria have been tied to peanuts, spinach, pistachios, alfalfa sprouts, cookie dough and numerous other products causing illness, and in some cases, loss of life.

Many factors affect the growth of microorganisms in food processing environments including the source of contamination, moisture, nutrients, pH, oxidation-reduction potential, temperature, presence or absence of inhibitors, interactions between microorganisms in a population, and time.

Where growth conditions may occur, it is important to limit the duration of exposure. In some processes, a product may pass through a temperature/moisture condition that is well suited for microbial growth. If the product has the potential to enter the process with some level of contamination (such as may be the case with some agricultural products), it is particularly important to limit the residence time at these conditions in order to avoid excessive populations of potentially harmful microorganisms.

Stagnant regions can occur at many points in a process, including conveyors, feeders, transfer chutes, and processing equipment such as product scrubbers, mills or dryers.

Storage vessels (surge hoppers, storage bins, IBCs, etc.) are of particular concern since a relatively large volume of material may be stagnant for a long period of time. A properly designed storage and discharge system for food applications must provide a first-in, first-out flow sequence that eliminates stagnant regions. Accomplishing this requires an understanding of how bulk solids behave during storage and flow.

Jenike & Johanson can test your ingredients and products and recommend appropriate hopper geometries and wall surface finishes to prevent stagnant regions during discharge and to ensure a first-in, first-out flow sequence.