TB can infect the digestive tract just fine. Coughing in proximity to you may result in a respiratory infection. Coughing on your food before bringing it to your table could set you up for the infection of the digestive tract. Either way, you don't want it. Food service workers need to be screened regularly. Workers with active disease need to be removed from employment in that field until they are clear.
Your point is well taken but those cases are quite rare and not easily detected; found this brief from S Agrawal, a researcher:
“Tuberculosis of the stomach and duodenum is rare in patients with pulmonary tuberculosis. Primary involvement is even rarer. Two cases of primary tuberculosis of the localised to the pyloro-duodenal area are presented. The most common symptoms are non-specific leading to a difficulty in establishing a pre-operative diagnosis. A high degree of suspicion is therefore required for its diagnosis and to differentiate it from more frequent causes of gastric outlet obstruction such as chronic peptic ulcer disease and gastric carcinoma. The treatment of gastric tuberculosis is primarily medical with anti-tuberculous drug therapy. The role of surgery lies in the cases with obstruction following hypertrophic tuberculosis. The surgery done is usually a gastroenterostomy. With the relative rate of extra-pulmonary tuberculosis increasing, tuberculosis of the pyloro-duodenal area should be considered in the differential diagnosis of gastric outlet obstruction.”
Point two:
These digestive cases are showing up mainly due to the increasing population of immuno-suppressed patients presenting.
I have a health nut sister in law who has not immunized her 2 and 4 year old sons. Any thoughts anybody? She also had taken them on several trips to Puerto Rico and Mexico. BTW, she herself is a nurse practitioner which is an advanced science degree.
She really irritated me when she demanded to know if the other chilren at her kids’ pre school were immunized.