The stomach stops working after death, creating a "gastronomic time capsule" of the victim's last meal. By examining the contents and degree of digestion in the stomach, forensic experts can estimate the time since the last meal and, therefore, the approximate time of death.The key factors that can be used to determine time of death from stomach contents are:

Size of the meal:
     A larger meal will take longer to digest than a smaller one. Light meals are typically fully digested within 1-2 hours, while medium-sized meals take 3-4 hours. Heavy meals can take 4-6 hours. If the small intestine is also empty, it indicates death probably took place at least 12 hours or more after the last meal. If the large intestine is also empty, death occurred over 24 hours ago.

Degree of digestion:
     The more digested the stomach contents are, the longer it has been since the last meal. Forensic experts can visually assess the level of digestion, ranging from no signs of digestion (level 1) to complete digestion with only liquid content remaining (level 4).

Types of food present:
     Different foods digest at different rates. For example, proteins and fats take longer to break down than carbohydrates. The presence and state of various food types can help narrow down the time since the last meal.

Bacterial and enzymatic activity:
     The stomach's digestive processes continue after death, but at a slower rate. Analyzing the effects of this continued digestion can also provide clues about the time elapsed.

DNA analysis:
     Emerging techniques like DNA metabarcoding can identify the specific plant and animal components of the last meal with high sensitivity and taxonomic resolution. This can reveal additional details about the timing and circumstances surrounding the last meal.

     By considering these various factors, forensic experts can often estimate the time of death within a few hours, which can be crucial evidence in criminal investigations. However, it's important to note that this is not an exact science, as digestion rates can vary based on individual differences and external factors like temperature. Especially when analyzing a round 2 case for HOSA, it is important to take into consideration location, ambient conditions, any medications or drugs found in the victim’s blood, and pretty much anything else.