Food sterilization significantly reduces the amount of microorganisms found in food, enabling producers to market only the highest quality products that meet the strictest food safety standards.
Dried spices and vegetables are agricultural products and therefore, by their very nature, contain various contaminants, including different species of bacteria and mold.
Non-sterilized spices reach the consumer carrying a multitude of contaminants prohibited for marketing by various institutional bodies. When bacteria, such as intestinal bacteria, are present, they can cause dangerous illnesses.
Research conducted in Israel and abroad, has revealed that a single gram of spices or dried vegetables can contain approximately 10^8 germs.
According to SII 1359, the level of contaminants permitted for 1 gram of seasonings or mixed spices is a maximum general count of 10^6, less than 10^3 coliforms, less than 10 E. coli, no salmonella presence in less than 25 grams, and no more than 10^4 mold propagules per gram.
These figures clearly indicate that dried spices and vegetables must be sterilized in order to meet Ministry of Health standards.
Treatment Methods for Minimizing Bacterial Load in Spices
Wet or Dry Heat Treatment
Chemical Treatment (Ethylene Oxide)
Gamma Ray Irradiation
Foods that contain oils and carbohydrates, such as salads for example, serve as an ideal breeding ground for bacteria.
Even using small amounts of spices in non-cooked food products will soon increase the bacterial count and bring the microbial load up to 100,000 times the initial level in that spice.
It follows that, without any preventative action to drastically reduce the amount of microorganisms in spices and vegetables, processed food products will be contaminated with high levels of bacteria, some of which pathogenic and dangerous to human health. In addition, food microorganisms can produce dangerous and carcinogenic toxins.
Although heat treatment effectively eradicates germs, there are concerns about harming the quality of the spice, especially with regards to the essential oils which give spices their taste and smell.
Irradiation is considered the recommended and favorable method for sterilization by all international bodies involved in food regulation (including the USDA, FDA etc.) as well as by worldwide health ministries. Radiation treatment eradicates microorganisms without opening the packaging, adding any chemicals, or triggering food activation.
The process is considered "cold" because the microbial load is decreased with only a negligible rise in temperature.
Irradiation in the appropriate dose does not damage the quality of the spice, nor does it leave any residue in the treated product and therefore, this process is considered the preferred and most effective of the various methods. At present, gamma ray irradiation is the world's leading and most widely accepted method for spice sterilization.
Gamma Ray Irradiation
Advantages of Gamma Ray Irradiation
Ease of Operation – Simplicity of operation is inversely proportional to the number of variables that need to be controlled. The greater the number of variables, the less reliable the process. Irradiation technology is the simplest and most reliable, as it has only one variable: exposure time. This variable is the easiest to control (compared to other processes which have several variables including: time, pressure, temperature, moisture, and gaseous concentration).
Reliability – The irradiation process is more reliable than alternative sterilization methods, as the source gamma rays is an isotope, which emits predictable and known radiation doses.
Product is Treated in its Final Packaging – The product is placed in its final packaging prior to sterilization, thus avoiding any possibility of re-contamination due to handling after sterilization.
Cold Process – there is no significant temperature rise during the irradiation process. This feature even allows for sterilization of products that are sensitive to heat, like plastics.
No Residue – There are no gaseous or toxic chemical residues, in contrast to chemical sterilization using toxic ethylene oxide, which results in the sterilized product containing gaseous or toxic chemical residues (absorption of some toxic gas, or its lethal byproducts like beta chloroethanol and ethylene glycol).
No Moisture – In this process, no moisture is introduced that would normally affect the product and its packaging.
Penetrability –gamma rays are capable to deeply penetrate products which ensures that the entire volume of the product is exposed to treatment. It is not dependent on heat convection or gas diffusion, as in alternative methods. This advantage permits irradiation of all types of containers and does not require special change in packaging.
Immediate Use – The product can be used immediately following sterilization (as opposed to processes involving ethylene oxide, following which the product must remain in isolation for a period of time, which increases the overall duration of the sterilization process).