Microbiological quality of by-products from the local oil and fat industry

Abstract

In the Republic of Moldova, oilseed cakes and vegetable oils are significant in industrial production, though their use remains mostly limited to animal feed. One major challenge to wider adoption in food production is ensuring the sanitary and microbiological quality of these by-products. Oilseed cakes are susceptible to microbial contamination during harvesting and storage. The oil extraction process has little effect on the initial contamination. During storage, the quantity and species composition of the microflora change: under optimal conditions, the number of non-

spore-forming bacteria decreases, while the number of spore-forming bacteria, resistant to unfavorable conditions, increases. Heat-resistant spore-forming bacteria remain in the oilseed cake and begin to proliferate under favorable conditions, leading to their predominance. Fungal microflora is also found in oilseed cakes. The main danger of mold fungi development in oilseed

by-products lies in their ability to produce mycotoxins. The microbiological profile of three locally sourced oilseed cakes – sunflower, almond, and pumpkin – was investigated. It was found that

sunflower oilseed cake had the highest total microbial cell count per 1 gram. Microflora quantitative analysis revealed the presence of aerobic putrefactive microorganisms such as Bac.

subtilis and Bac. mesentericus, as well as mesophilic anaerobes like Clostridium sporogenes. The representatives of mold fungi from the Penicillium and Aspergillus genera were also identified. In this regard, it is essential to focus on the quality control of oilseed cakes used in food production. They must be free from vegetative cells and spores of pathogenic and opportunistic microorganisms, as well as mold fungi capable of reproduction. It is also important to consider

that while technological operations can reduce microbial contamination, complete destruction is rarely achieved. Sometimes, pH and temperature during processing may even favor microbial growth. Given the microbiological condition of the studied oilseed cakes, their use can be

recommended for food technologies that include measures to reduce pathogenic microbial contamination.