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Mould prevention of pastries under high temperature and humidity conditions

Release time:

2014-10-30

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Abstract

Water activity represents the extent to which water in food can be utilized by microorganisms. In physical chemistry, water activity is the ratio of the water vapor pressure of food to the vapor pressure of pure water at the same temperature. It can be expressed by the formula aw = P/P0, or by relative equilibrium humidity as aw = ERH/100.

I. Main Factors Affecting the Shelf Life of Pastries

1. Product-inherent factors - significant impact of water activity

(1) Water activity is the main internal factor affecting the shelf life of pastries:
Water activity represents the extent to which water in food can be utilized by microorganisms. In physical chemistry, water activity is the ratio of the water vapor pressure of food to the vapor pressure of pure water at the same temperature. It can be expressed by the formula aw=P/P0, or by relative equilibrium humidity aw=ERH/100.
From the relationship between microbial activity and food water activity: all types of microorganisms require a certain water activity for growth. In other words, only when the water activity of food is greater than a certain critical value can specific microorganisms grow. Generally speaking, bacteria require aw>0.9, yeast aw>0.87, and mold aw>0.8.

(2) Food water activity is affected by various factors
Water content: The higher the water content of the product, the higher the water activity, and the easier it is for the product to mold;
Product sugar and salt content: For the same formula, the higher the sugar and salt content, the lower the water activity, and the less likely it is to mold;
Production and sales environment: The higher the temperature and humidity, the higher the water activity of the product, and the easier it is to mold;
Packaging environment: The better the packaging seal, the less the product is affected by external factors, and the more stable the water activity.

2. Product hygiene
Maintaining a good operating environment is conducive to preventing mold in products

3. Product preservation methods
Different preservation methods and the use of different preservatives will greatly affect the shelf life of the product.

II. Why is the mold prevention period shorter now compared to before, even with the same formula and process?

This is due to different temperature conditions. In hot and humid weather, the water activity increases first, greatly increasing the probability of product spoilage and worsening the pollution, making the product even more susceptible to mold.


III. What changes do we need to make?

1. In terms of formula: Appropriately reduce the amount of water added, or increase the amount of sugar to reduce water activity;

2. In terms of process: Under the existing baking process conditions, appropriately reduce the baking humidity and extend the baking time to dry the moisture and reduce the water activity;

3. Environmental control: Strengthen ventilation and dehumidification to reduce environmental humidity; increase the frequency of workshop sterilization to reduce the initial colony count in the workshop;

4. Packaging: Control packaging time, package immediately after cooling, and do not leave it for too long;

5. Strengthen product factory control: Strengthen the monitoring of water activity and initial colony count of products leaving the factory, and ensure product inspection;

6. Strengthen preservative control measures: In hot and humid weather, preservatives should be added at the maximum amount allowed by the national standards, and the most reasonable methods should be used.

For example: 40g individually packaged "Mobao Cake"

Normal weather:
Add 0.4% cake preservative to the total amount of cake, and spray 0.24ml of diluted liquid preservative (most of the product surface can be seen to be obviously moist);

Hot and humid weather:

Add 0.5% cake preservative to the total amount of cake, and spray 0.3ml of diluted liquid preservative (the product surface is more moist).

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