Re: How does temperature affect the mold growth in the 5 differentfood groups?

Hi Rachael,

When we talk about any type of microbial growth in foods there are several factors involved. The main ones are the nutrient content of the food needs to be enough to support growth - this is usually high in any food, the pH or acidity of the food, the temperature of the food needs to be within the gorwth range of the particular microorganism of interest, enough time at the proper temperature to allow growth to commence, the correct amount of oxygen for the particular microorganism, and enough water content.

For the foods you chose:

• Cheese - nutrient rich, acidic pH, inner portions don't have much oxygen - but outer portions do, and moisture level depends on the type of cheese. Soft cheeses, like cream cheese, have a much higher water content than hard cheeses, such as Cheddar. May contain preservatives to prevent mold growth.
  
• Apples - plenty of nutrients for molds, acidic pH, fairly high oxygen content, and high moisture content.
  
• Bread - plenty of nutrients for molds, slightly acidic pH, high in oxygen, fairly high in moisture. May contain preservatives to prevent mold growth.
  
• Cake - plenty of nutritents, fairly neutral pH, high in oxygen, high in moisture content - but water may be bound to solutes such as sugar and not available for microbial growth as readily. May contain preservatives.
  
• Brocolli - similar to apple, but less acidic pH
  
• Turkey - excellent growth medium for almost any microorganism. The bacteria naturally on the turkey will usually out compete molds and take over.

To get back to your question about temperature. Most molds will grow quite well if all conditions are right - at about room temperature. Depending on the species of mold involved, some can grow very well at refrigeration temperatueres. Not many foodborne-molds grow at freezer temperature though. Certain species of molds have heat resistant spores that can survive some cooking processes and then germinate and grow when the food is cooled. These species can be a problem in processed fruit products.

As for the food group, all the food groups contain many nutrients that would support the growth of molds. The best ways to prevent mold growth are to keep cold foods cold and hot foods hot, not to keep foods for too long - especially at temperatures that would allow growth, possibly use preservatives, and use proper sanitation methods when preparing foods.

I hope that answers your question.