Freezers and incubators maintain temperature as needed in experiments

Testing foods and beverages makes up a key component of keeping people safe. In experiments designed to analyze a range of features, the work often—almost always—requires some kind of temperature control. To keep samples warm, scientists use incubators; when cold is required, researchers might need a freezer. These common pieces of lab equipment can be used in many ways, and getting the right ones can play a crucial part in life-saving studies.

“Food and beverage quality control is an incredibly important part of ensuring the safety and quality of the things we consume,” notes NuAire (Plymouth, MN; https://www.nuaire.com/food-and-beverage). “This means that it’s essential to test for contaminants within edible products, and develop new production processes in order to provide better food and beverage quality control.”

In laboratories that test foods and beverages, scientists run many common tests. As examples, NuAire mentions “materials analysis and identification, contaminant identification, ingredient cross-contamination, off-colors, off-flavors, off-odors analysis and identification, extractables and leachables, failure analysis, packaging testing, consulting, method development, and more.” Plus, these labs deal with a wide range of samples. Here, NuAire points out: “fruits, vegetables, meats, dairy, grains, nuts, oils, proteins, candy, soft drinks, starches, sugars, vitamins, and more.”

So many kinds of tests and samples create many uses of incubators and freezers. It’s all aimed at making better and safer foods and beverages.

Keeping it cool

Consumers cool foods and beverages to keep them safer longer, but cooling is also used in many lab tests involving food safety. Plus, even deep levels of freezing have been used for some time.

In Ithaca, NY, researchers at Cornell University’s department of food science used cooling as part of testing how preservatives impacted measuring three components of milk—fat, lactose, and protein content—with mid-infrared (mid-IR) methods.1 The researchers used a –80° Celsius freezer to store unpreserved milk samples and different kinds of milk that included preservatives. Then, over 84 days, samples were removed and tested with mid-IR transmittance milk analyzers. The results varied by the kind of preservative used and which component was being measured.

The level of cooling required depends on the experiment at hand. In Ethiopia, for example, scientists used flame atomic absorption spectroscopy to measure the concentrations of trace metals in milk.2 This included essential and toxic elements, such as zinc and lead, respectively. In this work, researchers preserved the samples at –20 °C. The resulting measurements varied by the area where the milk was collected. For example, milk with the highest levels of trace metals came from an area with coal deposits, which caused “high mineral enrichment and metal leaching,” the authors wrote.

Controlling the surroundings

Instead of keeping samples cold, some analysis requires added heat. That calls for an incubator, which can also be used to control the environmental gases, such as carbon dioxide (CO2), in an experiment.

Sometimes, though, an incubator is just used to heat samples. In one example, scientists used incubation steps in testing samples for two plant toxins, gliadin and ricin.3 In using enzyme-linked immunosorbent assays (ELISAs), the researchers found that the length and temperature of incubation, along with other variables, affected the sensitivity of the tests.

Incubators can also be used to study the production of a product. As an example, scientists at Süleyman Demirel University (Isparta, Turkey) studied different ways to improve the production of kefir, a fermented milk product.4 Among other things, the researchers controlled the atmosphere during fermentation—ambient or 6% CO2. The results showed that the CO2 “did not provide a significant supporting effect on the biomass of kefir grains.”

From cooling and heating to controlling atmospheric gases, scientists use freezers and incubators in many kinds of food and beverage testing. Even in the limited—and dairy-heavy—examples described here, it’s clear that these devices help scientists keep foods and beverages safer. In some work, these tools help scientists find better ways to create some food products. So all sorts of testing can be done on the range of foods and beverages, and the best freezers and incubators help researchers keep the conditions under control.

References

  1. Barbano, D.M.; Wojciechowski, K.L. et al. Effect of preservatives on the accuracy of mid-infrared milk component testing. J. Dairy Sci. 2010, 93, 6000–11.
  2. Akele, M.L.; Abebe, D.Z. et al. Analysis of trace metal concentrations in raw cow’s milk from three dairy farms in North Gondar, Ethiopia: chemometric approach. Environ. Monit. Assess. 2017, 11, 499.
  3. Garber, E.A. and Thole, J. Application of microwave irradiation and heat to improve gliadin detection and ricin ELISA throughput with food samples. Toxins (Basel) 2015, 7, 135–44.
  4. Guzel-Seydim, Z.; Kok-Tas, T. et al. Effect of different growth conditions on biomass increase in kefir grains. J. Dairy Sci. 2011, 94, 1239–42.

Mike May is a freelance writer and editor living in Texas. He can be reached at [email protected]