Molds are opportunistic living microorganisms that feed on organic matter, therefore their ability to reproduce in foods. However, they can live in virtually any ecosystem or environment.
In the food industry, these microorganisms are usually seen as enemies. Yet similar to some bacteria, they can be beneficial for certain applications and are used to produce food ingredients and pharmaceutical products.
Mold in the bakery industry
In the bakery industry, along with staling, they are considered the main limiting factors for controlling products shelf-life. Molds that cause spoilage in bread include:
High-speed bakeries strive to keep mold away from their operations and products, especially in high water activity baked goods such as bread and buns. The following table highlights some of the strategies used in bakeries to prevent mold growth (or avoid their development):
Control factors
Comments
Best control levels / Strategies
Water availability (aw)
Lower water activity can effectively slow down mold growth.
Formulate bread to water activity levels below 0.95
Ingredients that help lower aw:
Polyols, glycerol
Small proteins (hydrolyzed proteins)
Sugars
Salt
pH
Low pH or acidic environments can limit mold growth. Acidic conditions can also impact the performance of mold inhibitors.
Lower the product pH to below 5.6
Low pHs can be achieved through:
Long fermentations
Use of lactic acid bacteria (LAB) (added or from sourdough)
Acidulants (weak organic acids, acid salts)
Fermented / cultured wheat, whey, corn
Vinegar, raisin juice
Organic material
Difficult to control since they are essential parts of bakery systems. Any animal or plant material can be used as food for mold.
Control here is focused on preventing accumulation of product on food-contact surfaces such as equipment, conveyors and others.
Proper documentation and implementation of GMP’s prerequisite programs (e.g. cleaning and sanitizing, employee practices, hygienic design).
Food management systems (e.g. HARPC of FSMA, HACCP, ISO 22000).
Temperature
Cooler storage and processing facility temperatures can slow down mold growth rate.
Kill-steps during processing (e.g. baking, extrusion cooking, pasteurization). Molds and yeast are usually inactivated when the interior temperature of the product reaches about 135–140°F (55–60°C).
Processing facility temperature: use HVAC systems to maintain temperatures around 68°F (20°C)
Product storage temperature: 60°F (15°C)
Bake to internal temperature of 205°F (96°C).
Thermal profiling is recommended.
Cooling to loaf internal temperature of 95–105°F (35–40°C) before packaging to prevent condensation.
Freezing and frozen storage.
Mold spores
Fungal spores are particularly widespread in bakeries due to their presence in flour and potential spread throughout the production environment via air movement.
Lack of proper cleaning and sanitation practices, recycling of extracted air and/or use of unfiltered air in the bakery increases the presence and accumulation of mold spores.
Use of ultraviolet or infrared radiation to inactivate mold and mold spores.
Use of modified, vacuum atmosphere or anti-microbialpackaging to inhibit mold growth.
Proper documentation and implementation of GMP’s prerequisite programs (e.g. air and water quality).
Preservatives
Undissociated (uncharged) weak acids diffuse through the microbial cell membrane to the cytoplasm, hindering cellular metabolic activities.2
Use of mold inhibitors
Calcium propionate (formulation)
Cultured wheat
Sorbate and acetate salts (topical)
Sorbic acid
Food safety considerations
Mold itself does not represent a food safety hazard for humans unless there is a serious allergy to food product bacteria. What does represent a hazard, however, is the toxins that they (especially, some species of Aspergillus) can produce. Such mycotoxins are extremely carcinogenic and mutagenic, and can cause serious diseases.3
Peanuts, tree nuts, cereals and milk can carry serious toxins that can be fatal to some people. One key consideration is that mycotoxins are not inactivated in the oven so control needs to be done at the source.
Types of mycotoxins that are poisonous to humans include:3
Aflatoxin
Vomitoxin
Ochratoxin
Post-baking mold contamination control
Post-baking steps are critical for mold control. Coming out of the oven, bread is virtually a sterile product but, upon contact with ambient air and unclean equipment surfaces, the product starts a very slow “mold recontamination process” at the crust (exposed areas). Cooling, slicing and packaging operations must, hence be carried out with high standards of hygiene to help reduce the risk of product infection.
References
Ray, B., and Bhunia, A. “Characteristics of Predominant Microorganisms in Food”. Fundamental Food Microbiology, 5th edition, CRC Press, Taylor & Francis Group, LLC, 2014, pp. 14–15.
Msagati, T.A.M. “Preservatives”. The Chemistry of Food Additives and Preservatives, John Wiley & Sons, Ltd, 2013, pp. 233–234.
Hutkins, R.W.. “Bread Fermentation”. Microbiology and Technology of Fermented Foods, Blackwell Publishing, 2006, pp. 261–298.
It consists of a series of steps including mixing, fermentation, makeup, proofing, baking, cooling, slicing and packaging. Due to their critical role, these processes must be carefully operated to meet pre-set conditions and specifications.
The function of moulding is to shape the dough piece, according to the bread variety being produced, so that it properly fits into pans. Dough moulding equipment can be set to achieve the desired shape with a minimum amount of stress and strain on the dough.
When the spores land on a suitable place, they begin to grow.They very quickly start making hyphae, small tendrils that look like roots. Hyphae are part of the mycelium. The mycelium is the main part of the mold, and grows inside the bread.
Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process.
The main difference between molding and casting is the use of the material in the process. Casting will typically involve metal, while molding focuses on plastics. In both cases, the melted material goes into a die or mold to create the final form.
Forming/moulding is an operation widely applied in the production of chocolate, bread, biscuits, confectionery and pies. Moulding is also an important process step in cheesemaking. Extrusion is widely used in the production of meat sausages, confectionery products and starchbased snack foods.
Introduction: My name is Trent Wehner, I am a talented, brainy, zealous, light, funny, gleaming, attractive person who loves writing and wants to share my knowledge and understanding with you.
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