It's in the carbohydrates and salt, not the mold.

http://www.livestrong.com/article/528241-fast-heart-rate-from-salt/

Also:

http://www.heart-palpitations.net/causes/heart-pounding-after-eating

...Some experience heart palpitations after eating. Some people only get an increased heart rate after eating sugar or processed foods. Sometimes heart palpitations (tachycardia) will happen even when just sitting, watching TV, laying down or just walking up the stairs.

We'll focus this article on the issues related to heart pounding after eating. Visit Pounding Heart Beat Causes to learn about other causes of pounding heart. You might also want to take a look at this article: Extra Heartbeat Causes.

There are several possible mechanisms as to why you experience rapid heartbeat after eating. Both increased and decreased of the heart rate with the ingestion of food and liquid are normal as digestion naturally increases the work of the heart. This can be seen from the changes in the blood flow as your stomach begins digesting a meal. Digesting food also puts extra demand on the body for oxygen. The occurrence of heart pounding from this process is possible although it may be a sign of problem with the circulation, the heart or the lung too.

People with poor digestion may experience heart palpitations after eating a heavy meal, particularly:

• Meal that riches in carbohydrate, sugar or fat such as chocolates;
• Food that are high in MSG, nitrates and sodium e.g. processed foods including pizza, lasagna, or foods high in oil;
• Food or drink that contain caffeine or other stimulants.

Some believe that this has something to do with the Vagus nerve which is shared by both the heart and the stomach. Some find that daily intake of Pantoprazole (Protonix), a medicine for indigestion, helps alleviate heart palpitations symptoms.

If you experience an increased heart rate after eating sugar, the amount of sugar you consumed also seems to affect how much pounding you get. You may feel like getting an adrenaline rush. Sometimes it is so bad that you can't go to sleep at night. It's also possible to experience shortness of breath, bloating and indigestion with it on occasion. The episodes of heart pounding usually begin within 30 to 60 minutes after eating a meal. The heart starts racing and sometimes goes up to 120 beats per minute or even more. It lasts up to 6 hours sometimes.

Moreover, those heavy meals such as pizza and lasagna have tons of sodium and saturated fat in them. If you do not drink enough water, your blood becomes thicker, and your heart will need to work harder. Also, cholesterol levels can spike right after a high saturated fat meal meaning your heart is overworking during this digestion process.

Increased heartbeat after eating certain foods may also sign a food sensitivity, even if you never had problems with food before. A food diary may clue you if this is the case.

Being overweight may also worsen the symptoms of heart pounding after eating.

If the heart pounds after eating is irregular or rapid, you could have cardiac arrhythmia such as premature ventricular contractions.

The cause of pounding heart after eating may turn out to be not related to heart problem at all. Severe acid reflux disorder (GERD) may cause the valve at the top of the stomach (between the esophagus and stomach) spasm. This may result in a sensation of the heart arbitrarily increasing the rate and beating faster and harder. Night sweats, anxiety attacks at night and heart palpitations after eating heavy meal might indicate heartburn from acid reflux.

Moreover, hiatus hernia may also cause palpitations after eating symptoms. Eating puts pressure in the stomach and hernia, which in turn puts pressure on the vagus nerve that controls the heart rate. It can also cause breathing difficulties.

The feeling of heart racing is very uncomfortable. It may make you feel very anxious and lead to a panic attack. Some people who experience rapid heartbeat after eating may get scared to the point where he or she skips meal to avoid racing or pounding heart symptoms. Others reduce the amount of food they consumed to keep away from the unpleasant and frightening episodes.

If your heart pounds after eating, you are suggested to divide your meals into several small meals and avoid large meals. This will avoid stressing the response on Vagus nerve and stabilize your blood sugar.

Sudden tachycardia / rapid heartbeat after eating may occur for no appearance reason. Completely changing your lifestyle should reduce the occurrence of heart palpitations after eating. Drink green tea after eating meals high in fat may help minimize the increase in heart rate. Some people find that drinking lots of water can help too.

Heart pounding after eating can be caused by any of the listed conditions or a combination. It could be as minor as acid reflux or food sensitivity to as major as liver or kidney damage. But it may be completely harmless since your heart works hardest when digesting food. You will have to have the proper diagnostic testing to determine your real problem and find the appropriate treatments that work for you.

"I don’t think it is after eating because it is more than six hours after food sometimes it happens in the night or early morning."

Food as well as prescriptions and supplements can have a delayed effect on heart rhythms and heart rates.  I know, I've been dealing with mine off and on for more than ten years.

I'll suggest one other thing and that is the possibility of sleep apnea.  People with sleep apnea rarely know that anything is wrong with them.  If you snore during sleep that is but one possible sign of it but not always.  

http://www.medterms.com/script/main/art.asp?articlekey=5510

Sleep apnea: The temporary stoppage of breathing during sleep, often resulting in daytime sleepiness. Apnea is a Greek word that means "want of breath."

The most common form of sleep apnea is obstructive sleep apnea. In obstructive sleep apnea, the muscles of the soft palate around the base of the tongue and the uvula relax, obstructing the airway. The airway obstruction causes the level of oxygen in the blood to fall (hypoxia), increases the stress on the heart, elevates blood pressure, and prevents the patient from entering REM sleep, the restful and restorative stage of sleep. In other words, sleep apnea causes deprivation of quality sleep.

The symptoms of obstructive sleep apnea include loud snoring and/or abnormal pattern of snoring with pauses and gasps. Other symptoms include excessive daytime sleepiness, memory changes, depression, and irritability. In some patients sleep apnea can contribute to high blood pressure, heart failure, stroke, and heart attack.

Obstructive sleep apnea typically affects middle-age, overweight men, and may affect women in later years. Obstructive apnea can be aggravated by alcohol, sleeping pills and tranquilizers taken at bedtime.

What is not mentioned in the above description is it also causes a rapid heart rate.  If your heart rate is rapid at night and early morning it could easily be from sleep apnea because you never know when it occurs - because you are asleep.  I know - I have it but I control it with a CPAP/breathing device and have done so for a couple of years now.  You can easily die from it and many do.

One cause (but not always) is being overweight.  If your BMI (body mass index) measurement is more than 25 then getting it under 25 should be your top priority.  (To calculate your BMI go here: http://nhlbisupport.com/bmi/)  It is overweight and/or obesity that causes a great deal of sleep apnea.  My BMI is consistently just under 25 but I do need to lose ten or twelve pounds to get to a more comfortable level.

How do you find out if you have sleep apnea?  I spent a night in a sleep clinic at a major hospital where they hook up about twenty four wires to you and monitor your heart rate, blood oxygen level and brain wave activity during sleep.  They do this via machines but also have a physician watching you through one-way glass.  If you you think that you'd be too embarrassed or too uncomfortable to get to sleep - it's not true.  If they diagnose you with sleep apnea at the sleep clinic they will bring you back for another night to determine which is the best CPAP and mask combination for you to cure the problem.  My insurance covered this $2,500 per night visit very well, only had about $50 out of pocket and I believe that it has saved my life.

The medical profession (but nobody in alternative medicine) can diagnose what you are dealing with and you can then choose how you wish to deal with it.