Do Toxins in food result a long onset time?

Not necessarily. The onset time of food poisoning symptoms can vary greatly depending on the toxin and the individual, and can range from hours to days. Some toxins, such as those produced by Staphylococcus aureus, can result in symptoms within as little as 30 minutes to six hours, while others, such as those produced by Clostridium botulinum, can take up to several days to cause symptoms.