Yes
Tears produce lysozyme to kill bacteria, gastric juice secretes Hcl that kills bacteria.
Yes, penicillin is often prescribed for gum and tooth infections.
Lemon juice can inhibit some bacteria if they are sensitive to lower (acidic) pH. As lemon juice is an acid. But there are very high numbers of bacteria in lemon wedges when tested. See link below:
Stomach bacteria is naturally neutralized with acidic or certain compounds in foods. If you drink lemon juice or orange juice, the bacteria will be suppressed. Also, compounds found in chili peppers are known to kill any bad bacteria.
Most bacteria as well as our cells work best at certain pH levels. Lemon juice has a pH of around 2. Our body has a pH around 7.4. Most bacteria prefer a pH of 7.
Cranberry juice is made by crushing cranberries and extracting their juice. The process involves cleaning the cranberries, crushing them, pressing the juice out, filtering it, pasteurizing it to kill bacteria, and then packaging it for sale.
To pasteurize juice at home, heat it to 160F (71C) for at least 15 seconds, then cool it quickly. This process helps kill harmful bacteria while preserving the juice's flavor and nutrients.
Pasteurization is a process of heating liquids to a certain temperature (not as high as boiling) to kill bacteria; it can be used for various drinks, such as milk, beer, or fruit juice.
Stomach digestive juice, also known as gastric juice, is acidic. It contains hydrochloric acid which helps break down food and kill bacteria in the stomach.
To pasteurize juice effectively, heat it to a specific temperature for a set amount of time to kill harmful bacteria while preserving flavor and nutrients. This process helps extend the shelf life of the juice.
Eating blackberries can help kill the oral bacteria that cause illness. Another benefit is that the juice is good for the heart.