Evaluating the effects of using plastic, silicone, and glass on time of sous vide cooking of gravy

  Background: Sous vide cooking is popular method of cooking involving a water bath with immersion circulator or a steam convection oven. This process is also known as low-temperature long-time method (LTLT), where food is held at a lower temperature over extended time for cooking (1). Plastic is the more commonly used medium with sous vide cooking. Glass and silicone are an environmentally alternative to plastic, since they are reusable mediums. These alternative mediums have not been studied and may affect the time to reach pasteurization. The purpose of this experiment is to determine how plastic, silicone, and glass influence time in sous vide cooking of gravy to 56.5°C. Methods: Four of each medium: plastic, silicone, and glass containing 500 mL of gravy with SmartButton data loggers at 4°C were introduced into a 56.5 °C water bath for 150 minutes. The data loggers recorded the temperature at one minute intervals. The data was used to run a One-Way Analysis of Variance (ANOVA) to analyze if there were any statistically significant differences between the three mediums and time, and a Scheffe’s test to compare the mean time of each of the mediums. Results: There was a difference in time of sous vide cooking for gravy at 56.5°C between the mediums: plastic, glass, silicone. The p-value was 0.00, therefore rejecting Ho and accepting there is a difference in time of sous vide cooking gravy at 56.5°C between the different mediums: plastic, glass, silicone. Comparing the mediums among each other, it showed that there was a difference between glass and silicone, glass and plastic and no significant difference between plastic and silicone medium. Conclusion: The results indicate that there is a statistically significant difference in time that it took for gravy to reach 56.5°C between the mediums: plastic, silicone, and glass. The mean time for each medium to reach 56.5°C differed; 65 minutes for plastic, 68 minutes for silicone, and 129 minutes for glass. This shows that a more environmentally friendly alternative to plastic sous vide pouches can be used. Silicone pouches show to be the best alternative, least compromising of the come-up and pasteurization time. If sous vide users opt to use glass, the come-up time almost doubles in time.