Decontamination of food-packing material using moist heat (original) (raw)
Related papers
International Journal of Food Microbiology, 2019
In the food industry, sterilization of packaging and filling machines by hydrogen peroxide (HP) is a widespread practice. Its effectiveness is usually tested by means of inactivation tests on selected test microorganisms that were any case chosen without taking into account that food products could be also spoiled by microorganisms presumably resistant to HP. For this reason, the aim of this work was to assess the resistance of different ascospore-forming moulds (Talaromyces bacillisporus, Aspergillus hiratsukae, Chaetomium globosum) to HP, in order to find the most resistant to this kind of chemical stress, and to compare their resistance with that registered for other moulds, including test microorganism Aspergillus brasiliensis ATCC 16404. Tests were carried out from 50 to 60°C on spores or conidia, depending on the strain, either by immersing inoculated strips (aluminium, tin-plate, HDPE, PET) in HP, or by directly inoculating cells in the sanitizing medium. In both tests, T. bacillisporus proved the most resistant strain, followed by A. hiratsukae, C. globosum and A. brasiliensis at all temperatures tested. In test without a supporting material, D values of T. bacillisporus varied from 6 to 23 s. In test with metallic or plastic strips, D values of T. bacillisporus were higher on plastic materials, compared to those obtained on metallic ones up to 53°C, whereas at higher temperatures D values proved similar. For A. hiratsukae, D values were similar if different materials were compared, except for D 50 on aluminium and HDPE, which proved slightly higher (3.1-3.4 s) than those obtained on tin-plate and PET (2.7-2.8 s). Analogously, ascospores of C. globosum behaved in a similar way if different materials were compared, except for D 50 values that varied in a wide range (from 2.9 s on tin-plate to 4.0 s on HDPE). A. brasiliensis was rapidly inactivated by the synergistic effect of heat and hydrogen peroxide, so for this strain it was not possible to calculate any D value. Based on the results obtained in this paper, tested ascospore-forming moulds proved to be sensibly more resistant to HP than other heat-sensitive strains tested, their D values always being significantly higher, regardless of the strain considered and the supporting material assessed. Ascospore-forming moulds could be furtherly investigated, as for practical purposes they seemed most suitable as target microorganisms than heat-sensitive microorganisms such as Aspergillus brasiliensis ATCC 16404, their use during bio-validations of sanitizing processes on machineries used for refrigerated products (pH > 4.5) or non-refrigerated acid products (pH ≤ 4.5) leading to more performing results.
A new high temperature short time process for microbial decontamination of seeds and food powders
Powder Technology, 2005
The process for heat treatment of seeds and food powders patented and developed by our laboratory is based on very short heat stresses (from 0.1 up to 30 s) at very high temperatures (in the range of 200 to 600 -C) followed by an instantaneous cooling due to a cold gas (À 80 -C). The decontamination of dried powders is difficult, and the difficulty correlates with the presence of a specific microflora adapted to low water content. Using this new thermal process, experiments with Bacillus subtilis spores and Saccharomyces cerevisiae cells dried on glass beads were carried out. Destruction levels obtained are in the range of 5 to 8 log according to initial water activity level. Our results showed that heat resistance of spores and vegetative cells was strongly improved for initial a w values in the range of 0.3 to 0.5. Our work also evaluated the effects of microbial distribution and powder granulometry on decontamination efficiency. The impact of heat treatment on product organoleptic qualities, notably color, has been also measured. D
Cleaning and Disinfection Procedures in the Food Industry General Aspects and Practical Applications
In the field of general prevention of infectious diseases, one of the most important issues concerns disinfection and sterilization, which both play a fundamental role in reducing the risk of infection. This is also true for the food industry, where these processes are used to produce the same outcomes. The different phases of cleaning and disinfection process of machines and of accessory parts (tanks, tubes etc.) with which foods come in contact are generally achieved by both physical and chemical means. These processes should result in cleaning, disinfection and removal of foreign bodies from with the structures of the equipment being cleaned. 1. Definitions Cleaning/cleansing: a series of combined operations aiming at the elimination of dirt from the surface areas of equipment or from materials, through the use of chemical and physical means; Disinfection: elimination on a given substrate of pathogen microorganisms, viruses and bacteria, in a vegetative form through the use of ch...
Decontamination of food products with superheated steam
Journal of Food Engineering, 2007
Food products can often be contaminated with mycotoxins and spores, many of which are resistant to heat. To ensure the safety of our food supply they must be reduced or eliminated from the final product through processing procedures. The effects of superheated steam (SS) as a processing medium on grains contaminated with the Fusarium mycotoxin deoxynivalenol (DON) and with Geobacillus stearothermophilus spores are presented here. The processing temperature was between 110 and 185°C with three steam velocities of 0.65, 1.3 and 1.5 m/s for DON contaminated wheat and between 105 and 175°C at one steam velocity of 0.35 m/s for mixture of sand and spores. Reductions in DON concentration of up to 52% were achieved at 185°C and 6 min processing time. This was due only to thermal degradation and not to solubilization and extraction. The effect of processing with SS on heat resistant spores was conducted for processing times of 0.5-480 min. The thermal resistance constant for G. stearothermophilus was determined to be 28.4°C for the SS processing temperature of 130-175°C. The first 5 min of SS processing were most effective in the reduction of spores. The use of SS has proven itself to be beneficial by reducing the contamination in foods in addition to any drying that may occur.
Thermal Inactivation of Microorganisms
Critical Reviews in Food Science and Nutrition, 2014
This paper serves as an overview of various aspects of thermal processing. Heat processing of foods has a long history and is still one of the most important preservation methods. To guarantee microbiological safety and stability, large safety margins are often applied in traditional heat processes. Because of the need for more fresh like foods, there is a need for milder preservation methods without compromising on safety and stability. The review deals with heat resistance data and mathematical models that describe heat inactivation. The effects of food composition are not yet fully clear and more knowledge of the cell physiology of the target microorganism could be of help in predicting the effects of food constituents. Finally, special attention has been paid to biological time temperature indicators to enable proper process calculations.
Evaluation of a system for chemical sterilization of packages
Packaging Technology and Science, 2004
A system was evaluated for the chemical sterilization of packages, based on its sporicidal efficiency using inoculated Bacillus subtilis inside polyethylene terephthalate (PET) bottles. Different combinations of contact time, temperature and peracetic acid concentrations were tested, delineated according to a factorial planning of 2 3. The results, expressed as decimal reduction counts, proved that peracetic acid showed good sporicidal efficiency at 1.2% concentration in the temperature range 30-50°C. With this performance, the tested system can be used to sterilize plastic bottles and other similar packages, achieving a count reduction of spores by up to 10-7 .
Journal of Applied Microbiology, 2006
To determine the effectiveness of a novel dry air decontamination apparatus in the deactivation of Salmonella serotype Typhimurium DT104 or Escherichia coli O157:H7 on beef surfaces. Methods and Results: A laboratory scale dry air decontamination apparatus, capable of producing repeatable and known heating time-temperature cycles on food surfaces was used in decontamination trials. Beef samples were surface inoculated with 7-8 log 10 CFU cm )2 of S. Typhimurium DT104 or E. coli O157:H7 and heated at 60, 75, 90 and 100°C using fast and slow heating rates and subsequently held at these temperatures for up to 600 s. A substantial reduction in pathogen numbers was achieved at higher temperatures (90 and 100°C, 4AE18-6AE06 log 10 CFU cm )2 ) using both heating rates, but cell survival at these temperatures was also observed. At the lower temperatures, deactivation was small at 60°C in particular it was less than one log unit after 3 min heating. No significant differences were observed when total reductions in pathogen counts were compared for all the temperature/heat up time combinations tested. During slow heating at 90°C, and both heating rates at 100°C, the pattern of deactivation of S. Typhimurium DT104 or E. coli O157:H7 was triphasic. Conclusions: This study has shown that heating meat surfaces with dry air can achieve substantial reductions in S. Typhimurium DT104 or E. coli O157:H7. As surface decontamination of beef surfaces with dry air had a negative effect on beef colour and appearance, such a decontamination apparatus would be unsuitable for producing meat for retail sale but it could be used to produce safer meat for use in the catering trade. Significance and Impact of the Study: This study provides researchers and food processors with data on the dynamic changes in S. Typhimurium DT104 and E. coli O157:H7 counts on intact beef surfaces during heating with dry air under realistic (time-varying) temperature conditions.
Combination methods for microbial decontamination
2003
Novel methods to improve the microbiological quality and to extend the shelf life of foods would be advantageous. In this study, the killing effect of UV, laser, microwave radiation, conventional heating and ozone was investigated, alone and in various combinations, on saline suspensions and agar plate cultures of Listeria monocytogenes, Salmonella typhimurium, Campylobacter jejuni, Shewanella putrefaciens, Pseudomonas fragi, Micrococcus luteus and on E. coli (lux) as an indicator organism. E. coli (lux) was the most sensitive to the effect of UV, whereas M. luteus was the most resistant to UV and Nd:YAG laser radiation. S. putrefaciens was the most sensitive bacterium to Nd:YAG laser radiation. With microwave treatment, a temperature between 70-71°C was the critical point for killing bacteria by microwave energy, although there was evidence of an athermal effect of microwave on bacteria. Ozone was effective against the bacteria used, although the killing of bacteria on the foodstuf...