Introduction
There is an increasing interest with food entrepreneurs and processors making hummus. Hummus is a delicious spread and dip which is made from chickpeas and other ingredients and can be made in a variety of flavors. This article will describe how to safely make hummus. Lastly, this article will conclude with the regulations that processors must abide by in order to sell hummus in South Dakota.
Ingredients
The ingredients used for this product include chickpeas which can either be canned or dry. If the chickpeas are in the dry form, they may or may not be pasteurized. Chickpeas that are canned will be pasteurized. The chickpeas are high in protein and fiber and make up much of the recipe. Tahini paste, which is made up of sesame seeds, oil, and salt may or may not be pasteurized. The sesame seeds in the tahini paste may or may not be pasteurized. If the sesame seeds are pasteurized, they may be pasteurized by roasting or by another pasteurization method. Since sesame seeds are an agricultural product, they are susceptible to potentially having pathogens such as L. monocytogenes or salmonella. Therefore, it is essential to understand if the tahini sauce is pasteurized. The tahini sauce also contributes flavor and texture to the hummus.
Lemon juice is added to contribute flavor to the hummus, and the amount of lemon juice can vary depending on taste preference. Olive oil is added for flavor and texture. Garlic, cumin, or other vegetables are added to contribute flavor. The strength of the garlic will change the flavor profile of the hummus depending on if it’s raw and more pungent. Spices are added to contribute different flavor profiles. Any vegetable, herb, or spice that is added as part of the recipe is susceptible to having pathogens depending on if the herb or spice has been treated or if the vegetable has been treated and washed. Salt is added to contribute and enhance the flavors in the hummus. Water can also be added at the mixing/pureeing step to improve the texture.
Thus, we see that given the risk of the ingredients, it’s important to understand if the ingredients are pasteurized. If the ingredients are not pasteurized, the hummus will need to be pasteurized in order to be considered ready-to-eat. For the purposes of this article, we will treat the ingredients as if they are not pasteurized and because the ingredients are not pasteurized, we will treat the hummus as needing to be pasteurized.
Process
For the process, we’ll be discussing how hummus is made at a residential level, rather than at a large or commercial scale level. Although the processor may change the order in how they process, the steps as described below are the general steps in making hummus.
Soak or Cook Chickpeas
The chickpeas will need to soak or be cooked prior to being made into a pureed paste. Soaking times and cooking times may vary by processor. Some processors will choose to cook the chickpeas by bringing them to a boil for a certain amount of time. Other processors may choose to let the chickpeas soak for a certain amount of time. The soaking or cooking allows the chickpeas to become soft in order to achieve a desired texture.
Mixing and Pureed
The chickpeas will need to be made into a pureed texture. To achieve a pureed texture, the chickpeas can be added to a food processor or mixer. The chickpeas will then be mechanically changed into a pureed paste form. Some processors may vary in how they mix and puree. For example, some processors may mix the tahini and oil first. Other processors may mix and puree the chickpeas first and then add the ingredients after the chickpeas have been pureed. Other processors may choose to mix and puree all the ingredients together in one step. However, the processor chooses to make their hummus, they will need to make the chickpeas into a paste and then add the other ingredients to achieve a smooth texture and homogenous product mixture. Mixing all ingredients together is essential to ensure a homogenous mixture as well as ensure emulsification of the water and oil components.
Water Activity and pH of Hummus
Generally speaking, hummus has a high water activity which can range from 0.95 to 0.99. The pH of hummus can also range but it is generally around 4.4. The water activity and pH of hummus will support pathogen growth if there is the presence of pathogens.
Pasteurization
The FDA has published time and temperature parameters for the inactivation of Listeria monocytogenes for high water activity food with pH near neutrality (1). Below is the table that gives time, temperature, and the associated lethality rate.
| Internal Product Temperature (°F) | Internal Product Temperature (°C) | Lethal Rate | Time for 6D Process (Minutes) |
|---|---|---|---|
| 145 | 63 | 0.117 | 17 |
| 147 | 64 | 0.158 | 12.7 |
| 149 | 65 | 0.215 | 9.3 |
| 151 | 66 | 0.293 | 6.8 |
| 153 | 67 | 0.398 | 5 |
| 154 | 68 | 0.541 | 3.7 |
| 156 | 69 | 0.736 | 2.7 |
| 158 | 70 | 1 | 2 |
| 160 | 71 | 1.359 | 1.5 |
| 162 | 72 | 1.848 | 1 |
| 163 | 73 | 2.512 | 0.8 |
| 165 | 74 | 3.415 | 0.6 |
| 167 | 75 | 4.642 | 0.4 |
| 169 | 76 | 6.31 | 0.3 |
| 171 | 77 | 8.577 | 0.2 |
| 172 | 78 | 11.659 | 0.2 |
| 174 | 79 | 15.849 | 0.1 |
| 176 | 80 | 21.544 | 0.09 |
| 178 | 81 | 29.286 | 0.07 |
| 180 | 82 | 39.81 | 0.05 |
| 182 | 83 | 54.116 | 0.03 |
| 183 | 84 | 73.564 | 0.03 |
| 185 | 85 | 100 | 0.02 |
Note: z = 13.5°F (7.5°C)
Additionally, there was a thesis done to look at strategies for small-scale production of hummus products. In this article, it was found that hummus that had a pH of 4.2, but had no preservatives and was hot-filled at 87.8°C or 190°F after 10 days of incubation at 35°C, none of the incubated samples had mold growth which were hot-filled at 190°F (2). Therefore, a pasteurization temperature in Table A-3 needs to be achieved to properly pasteurize the hummus and a hot fill temperature of 190°F should be targeted to eliminate mold and improve the shelf life of the product.
Packaging
The container used to package the hummus may vary but typical packaging for hummus includes a plastic container, flexible seal, and plastic snap-on top. As mentioned earlier, a hot-fill process should be used to pasteurize the packaging material. The typical hot fill process includes heating the product to the desired temperature, filling the hot product into the finished container, sealing the container, and then inverting for a defined period of time (typically 2 minutes or longer) to heat the top head space of the packaging material. This hot fill process will ensure that the packaging material is pasteurized and the risk of post-process handling and contamination is controlled and will improve shelf life of the hummus. Hummus will need to be stored in refrigerated conditions.
Regulatory
Hummus does not fall under the cottage food laws. Therefore, to produce and sell hummus in South Dakota, it would need to be produced and processed in a licensed kitchen by the South Dakota Department of Health. The South Dakota Department of Health would ensure that this product is produced out of a licensed kitchen and would also ensure that proper pasteurization and hot-filling procedures are followed. Additionally, SD DOH code allows for a licensed kitchen to make a non-pasteurized hummus product but it would require product refrigeration and date marking (must consume or discard within 10 days of preparation). This would be for hummus that is for immediate service and not packaged.
Closing
Hummus is a tasty and exciting new food that food entrepreneurs and processors are experimenting with. The goal of this article is to help food entrepreneurs understand the critical food safety hazards and quality concerns that need to be addressed when making this product in order to sell it. If you’re looking to process and sell your hummus product, be sure that it is made safely and according to South Dakota regulations.
Notes
- U.S. Food and Drug Administration. APPENDIX 4: Bacterial Pathogen Growth and Inactivation.
- Pazlopez, C. (2014). Strategies for Small-Scale Production of Dried Apples and Hummus Products with Natural Ingredients. [Master’s Thesis, Cornell University].
